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070b8750b0963cf00e4b9c3c147dd0eb8690fefe
cpython-source-deps/generic/tkImgPhInstance.c
Steve Dower 070b8750b0 Import Tk 8.6.11
2021-03-30 00:54:10 +01:00

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/*
* tkImgPhInstance.c --
*
* Implements the rendering of images of type "photo" for Tk. Photo
* images are stored in full color (32 bits per pixel including alpha
* channel) and displayed using dithering if necessary.
*
* Copyright (c) 1994 The Australian National University.
* Copyright (c) 1994-1997 Sun Microsystems, Inc.
* Copyright (c) 2002-2008 Donal K. Fellows
* Copyright (c) 2003 ActiveState Corporation.
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* Author: Paul Mackerras (paulus@cs.anu.edu.au),
* Department of Computer Science,
* Australian National University.
*/
#include "tkImgPhoto.h"
#include "tkPort.h"
/*
* Declaration for internal Xlib function used here:
*/
extern int _XInitImageFuncPtrs(XImage *image);
/*
* Forward declarations
*/
#ifndef TKPUTIMAGE_CAN_BLEND
static void BlendComplexAlpha(XImage *bgImg, PhotoInstance *iPtr,
int xOffset, int yOffset, int width, int height);
#endif
static int IsValidPalette(PhotoInstance *instancePtr,
const char *palette);
static int CountBits(pixel mask);
static void GetColorTable(PhotoInstance *instancePtr);
static void FreeColorTable(ColorTable *colorPtr, int force);
static void AllocateColors(ColorTable *colorPtr);
static void DisposeColorTable(ClientData clientData);
static int ReclaimColors(ColorTableId *id, int numColors);
/*
* Hash table used to hash from (display, colormap, palette, gamma) to
* ColorTable address.
*/
static Tcl_HashTable imgPhotoColorHash;
static int imgPhotoColorHashInitialized;
#define N_COLOR_HASH (sizeof(ColorTableId) / sizeof(int))
/*
*----------------------------------------------------------------------
*
* TkImgPhotoConfigureInstance --
*
* This function is called to create displaying information for a photo
* image instance based on the configuration information in the model.
* It is invoked both when new instances are created and when the model
* is reconfigured.
*
* Results:
* None.
*
* Side effects:
* Generates errors via Tcl_BackgroundException if there are problems in
* setting up the instance.
*
*----------------------------------------------------------------------
*/
void
TkImgPhotoConfigureInstance(
PhotoInstance *instancePtr) /* Instance to reconfigure. */
{
PhotoModel *modelPtr = instancePtr->masterPtr;
XImage *imagePtr;
int bitsPerPixel;
ColorTable *colorTablePtr;
XRectangle validBox;
/*
* If the -palette configuration option has been set for the model, use
* the value specified for our palette, but only if it is a valid palette
* for our windows. Use the gamma value specified the model.
*/
if ((modelPtr->palette && modelPtr->palette[0])
&& IsValidPalette(instancePtr, modelPtr->palette)) {
instancePtr->palette = modelPtr->palette;
} else {
instancePtr->palette = instancePtr->defaultPalette;
}
instancePtr->gamma = modelPtr->gamma;
/*
* If we don't currently have a color table, or if the one we have no
* longer applies (e.g. because our palette or gamma has changed), get a
* new one.
*/
colorTablePtr = instancePtr->colorTablePtr;
if ((colorTablePtr == NULL)
|| (instancePtr->colormap != colorTablePtr->id.colormap)
|| (instancePtr->palette != colorTablePtr->id.palette)
|| (instancePtr->gamma != colorTablePtr->id.gamma)) {
/*
* Free up our old color table, and get a new one.
*/
if (colorTablePtr != NULL) {
colorTablePtr->liveRefCount -= 1;
FreeColorTable(colorTablePtr, 0);
}
GetColorTable(instancePtr);
/*
* Create a new XImage structure for sending data to the X server, if
* necessary.
*/
if (instancePtr->colorTablePtr->flags & BLACK_AND_WHITE) {
bitsPerPixel = 1;
} else {
bitsPerPixel = instancePtr->visualInfo.depth;
}
if ((instancePtr->imagePtr == NULL)
|| (instancePtr->imagePtr->bits_per_pixel != bitsPerPixel)) {
if (instancePtr->imagePtr != NULL) {
XDestroyImage(instancePtr->imagePtr);
}
imagePtr = XCreateImage(instancePtr->display,
instancePtr->visualInfo.visual, (unsigned) bitsPerPixel,
(bitsPerPixel > 1? ZPixmap: XYBitmap), 0, NULL,
1, 1, 32, 0);
instancePtr->imagePtr = imagePtr;
/*
* We create images using the local host's endianness, rather than
* the endianness of the server; otherwise we would have to
* byte-swap any 16 or 32 bit values that we store in the image
* if the server's endianness is different from ours.
*/
if (imagePtr != NULL) {
#ifdef WORDS_BIGENDIAN
imagePtr->byte_order = MSBFirst;
#else
imagePtr->byte_order = LSBFirst;
#endif
_XInitImageFuncPtrs(imagePtr);
}
}
}
/*
* If the user has specified a width and/or height for the model which is
* different from our current width/height, set the size to the values
* specified by the user. If we have no pixmap, we do this also, since it
* has the side effect of allocating a pixmap for us.
*/
if ((instancePtr->pixels == None) || (instancePtr->error == NULL)
|| (instancePtr->width != modelPtr->width)
|| (instancePtr->height != modelPtr->height)) {
TkImgPhotoInstanceSetSize(instancePtr);
}
/*
* Redither this instance if necessary.
*/
if ((modelPtr->flags & IMAGE_CHANGED)
|| (instancePtr->colorTablePtr != colorTablePtr)) {
TkClipBox(modelPtr->validRegion, &validBox);
if ((validBox.width > 0) && (validBox.height > 0)) {
TkImgDitherInstance(instancePtr, validBox.x, validBox.y,
validBox.width, validBox.height);
}
}
}
/*
*----------------------------------------------------------------------
*
* TkImgPhotoGet --
*
* This function is called for each use of a photo image in a widget.
*
* Results:
* The return value is a token for the instance, which is passed back to
* us in calls to TkImgPhotoDisplay and ImgPhotoFree.
*
* Side effects:
* A data structure is set up for the instance (or, an existing instance
* is re-used for the new one).
*
*----------------------------------------------------------------------
*/
ClientData
TkImgPhotoGet(
Tk_Window tkwin, /* Window in which the instance will be
* used. */
ClientData modelData) /* Pointer to our model structure for the
* image. */
{
PhotoModel *modelPtr = modelData;
PhotoInstance *instancePtr;
Colormap colormap;
int mono, nRed, nGreen, nBlue, numVisuals;
XVisualInfo visualInfo, *visInfoPtr;
char buf[TCL_INTEGER_SPACE * 3];
XColor *white, *black;
XGCValues gcValues;
/*
* Table of "best" choices for palette for PseudoColor displays with
* between 3 and 15 bits/pixel.
*/
static const int paletteChoice[13][3] = {
/* #red, #green, #blue */
{2, 2, 2, /* 3 bits, 8 colors */},
{2, 3, 2, /* 4 bits, 12 colors */},
{3, 4, 2, /* 5 bits, 24 colors */},
{4, 5, 3, /* 6 bits, 60 colors */},
{5, 6, 4, /* 7 bits, 120 colors */},
{7, 7, 4, /* 8 bits, 198 colors */},
{8, 10, 6, /* 9 bits, 480 colors */},
{10, 12, 8, /* 10 bits, 960 colors */},
{14, 15, 9, /* 11 bits, 1890 colors */},
{16, 20, 12, /* 12 bits, 3840 colors */},
{20, 24, 16, /* 13 bits, 7680 colors */},
{26, 30, 20, /* 14 bits, 15600 colors */},
{32, 32, 30, /* 15 bits, 30720 colors */}
};
/*
* See if there is already an instance for windows using the same
* colormap. If so then just re-use it.
*/
colormap = Tk_Colormap(tkwin);
for (instancePtr = modelPtr->instancePtr; instancePtr != NULL;
instancePtr = instancePtr->nextPtr) {
if ((colormap == instancePtr->colormap)
&& (Tk_Display(tkwin) == instancePtr->display)) {
/*
* Re-use this instance.
*/
if (instancePtr->refCount == 0) {
/*
* We are resurrecting this instance.
*/
Tcl_CancelIdleCall(TkImgDisposeInstance, instancePtr);
if (instancePtr->colorTablePtr != NULL) {
FreeColorTable(instancePtr->colorTablePtr, 0);
}
GetColorTable(instancePtr);
}
instancePtr->refCount++;
return instancePtr;
}
}
/*
* The image isn't already in use in a window with the same colormap. Make
* a new instance of the image.
*/
instancePtr = ckalloc(sizeof(PhotoInstance));
instancePtr->masterPtr = modelPtr;
instancePtr->display = Tk_Display(tkwin);
instancePtr->colormap = Tk_Colormap(tkwin);
Tk_PreserveColormap(instancePtr->display, instancePtr->colormap);
instancePtr->refCount = 1;
instancePtr->colorTablePtr = NULL;
instancePtr->pixels = None;
instancePtr->error = NULL;
instancePtr->width = 0;
instancePtr->height = 0;
instancePtr->imagePtr = 0;
instancePtr->nextPtr = modelPtr->instancePtr;
modelPtr->instancePtr = instancePtr;
/*
* Obtain information about the visual and decide on the default palette.
*/
visualInfo.screen = Tk_ScreenNumber(tkwin);
visualInfo.visualid = XVisualIDFromVisual(Tk_Visual(tkwin));
visInfoPtr = XGetVisualInfo(Tk_Display(tkwin),
VisualScreenMask | VisualIDMask, &visualInfo, &numVisuals);
if (visInfoPtr == NULL) {
Tcl_Panic("TkImgPhotoGet couldn't find visual for window");
}
nRed = 2;
nGreen = nBlue = 0;
mono = 1;
instancePtr->visualInfo = *visInfoPtr;
switch (visInfoPtr->c_class) {
case DirectColor:
case TrueColor:
nRed = 1 << CountBits(visInfoPtr->red_mask);
nGreen = 1 << CountBits(visInfoPtr->green_mask);
nBlue = 1 << CountBits(visInfoPtr->blue_mask);
mono = 0;
break;
case PseudoColor:
case StaticColor:
if (visInfoPtr->depth > 15) {
nRed = 32;
nGreen = 32;
nBlue = 32;
mono = 0;
} else if (visInfoPtr->depth >= 3) {
const int *ip = paletteChoice[visInfoPtr->depth - 3];
nRed = ip[0];
nGreen = ip[1];
nBlue = ip[2];
mono = 0;
}
break;
case GrayScale:
case StaticGray:
nRed = 1 << visInfoPtr->depth;
break;
}
XFree((char *) visInfoPtr);
if (mono) {
sprintf(buf, "%d", nRed);
} else {
sprintf(buf, "%d/%d/%d", nRed, nGreen, nBlue);
}
instancePtr->defaultPalette = Tk_GetUid(buf);
/*
* Make a GC with background = black and foreground = white.
*/
white = Tk_GetColor(modelPtr->interp, tkwin, "white");
black = Tk_GetColor(modelPtr->interp, tkwin, "black");
gcValues.foreground = (white != NULL)? white->pixel:
WhitePixelOfScreen(Tk_Screen(tkwin));
gcValues.background = (black != NULL)? black->pixel:
BlackPixelOfScreen(Tk_Screen(tkwin));
Tk_FreeColor(white);
Tk_FreeColor(black);
gcValues.graphics_exposures = False;
instancePtr->gc = Tk_GetGC(tkwin,
GCForeground|GCBackground|GCGraphicsExposures, &gcValues);
/*
* Set configuration options and finish the initialization of the
* instance. This will also dither the image if necessary.
*/
TkImgPhotoConfigureInstance(instancePtr);
/*
* If this is the first instance, must set the size of the image.
*/
if (instancePtr->nextPtr == NULL) {
Tk_ImageChanged(modelPtr->tkMaster, 0, 0, 0, 0,
modelPtr->width, modelPtr->height);
}
return instancePtr;
}
/*
*----------------------------------------------------------------------
*
* BlendComplexAlpha --
*
* This function is called when an image with partially transparent
* pixels must be drawn over another image. It blends the photo data onto
* a local copy of the surface that we are drawing on, *including* the
* pixels drawn by everything that should be drawn underneath the image.
*
* Much of this code has hard-coded values in for speed because this
* routine is performance critical for complex image drawing.
*
* Results:
* None.
*
* Side effects:
* Background image passed in gets drawn over with image data.
*
* Notes:
* This should work on all platforms that set mask and shift data
* properly from the visualInfo. RGB is really only a 24+ bpp version
* whereas RGB15 is the correct version and works for 15bpp+, but it
* slower, so it's only used for 15bpp+.
*
* Note that Win32 pre-defines those operations that we really need.
*
*----------------------------------------------------------------------
*/
#ifndef TKPUTIMAGE_CAN_BLEND
#ifndef _WIN32
#define GetRValue(rgb) (UCHAR(((rgb) & red_mask) >> red_shift))
#define GetGValue(rgb) (UCHAR(((rgb) & green_mask) >> green_shift))
#define GetBValue(rgb) (UCHAR(((rgb) & blue_mask) >> blue_shift))
#define RGB(r, g, b) ((unsigned)( \
(UCHAR(r) << red_shift) | \
(UCHAR(g) << green_shift) | \
(UCHAR(b) << blue_shift) ))
#define RGB15(r, g, b) ((unsigned)( \
(((r) * red_mask / 255) & red_mask) | \
(((g) * green_mask / 255) & green_mask) | \
(((b) * blue_mask / 255) & blue_mask) ))
#endif /* !_WIN32 */
static void
BlendComplexAlpha(
XImage *bgImg, /* Background image to draw on. */
PhotoInstance *iPtr, /* Image instance to draw. */
int xOffset, int yOffset, /* X & Y offset into image instance to
* draw. */
int width, int height) /* Width & height of image to draw. */
{
int x, y, line;
unsigned long pixel;
unsigned char r, g, b, alpha, unalpha, *modelPtr;
unsigned char *alphaAr = iPtr->masterPtr->pix32;
/*
* This blending is an integer version of the Source-Over compositing rule
* (see Porter&Duff, "Compositing Digital Images", proceedings of SIGGRAPH
* 1984) that has been hard-coded (for speed) to work with targetting a
* solid surface.
*
* The 'unalpha' field must be 255-alpha; it is separated out to encourage
* more efficient compilation.
*/
#define ALPHA_BLEND(bgPix, imgPix, alpha, unalpha) \
((bgPix * unalpha + imgPix * alpha) / 255)
/*
* We have to get the mask and shift info from the visual on non-Win32 so
* that the macros Get*Value(), RGB() and RGB15() work correctly. This
* might be cached for better performance.
*/
#ifndef _WIN32
unsigned long red_mask, green_mask, blue_mask;
unsigned long red_shift, green_shift, blue_shift;
Visual *visual = iPtr->visualInfo.visual;
red_mask = visual->red_mask;
green_mask = visual->green_mask;
blue_mask = visual->blue_mask;
red_shift = 0;
green_shift = 0;
blue_shift = 0;
while ((0x0001 & (red_mask >> red_shift)) == 0) {
red_shift++;
}
while ((0x0001 & (green_mask >> green_shift)) == 0) {
green_shift++;
}
while ((0x0001 & (blue_mask >> blue_shift)) == 0) {
blue_shift++;
}
#endif /* !_WIN32 */
/*
* Only UNIX requires the special case for <24bpp. It varies with 3 extra
* shifts and uses RGB15. The 24+bpp version could also then be further
* optimized.
*/
#if !defined(_WIN32)
if (bgImg->depth < 24) {
unsigned char red_mlen, green_mlen, blue_mlen;
red_mlen = 8 - CountBits(red_mask >> red_shift);
green_mlen = 8 - CountBits(green_mask >> green_shift);
blue_mlen = 8 - CountBits(blue_mask >> blue_shift);
for (y = 0; y < height; y++) {
line = (y + yOffset) * iPtr->masterPtr->width;
for (x = 0; x < width; x++) {
modelPtr = alphaAr + ((line + x + xOffset) * 4);
alpha = modelPtr[3];
/*
* Ignore pixels that are fully transparent
*/
if (alpha) {
/*
* We could perhaps be more efficient than XGetPixel for
* 24 and 32 bit displays, but this seems "fast enough".
*/
r = modelPtr[0];
g = modelPtr[1];
b = modelPtr[2];
if (alpha != 255) {
/*
* Only blend pixels that have some transparency
*/
unsigned char ra, ga, ba;
pixel = XGetPixel(bgImg, x, y);
ra = GetRValue(pixel) << red_mlen;
ga = GetGValue(pixel) << green_mlen;
ba = GetBValue(pixel) << blue_mlen;
unalpha = 255 - alpha; /* Calculate once. */
r = ALPHA_BLEND(ra, r, alpha, unalpha);
g = ALPHA_BLEND(ga, g, alpha, unalpha);
b = ALPHA_BLEND(ba, b, alpha, unalpha);
}
XPutPixel(bgImg, x, y, RGB15(r, g, b));
}
}
}
return;
}
#endif /* !_WIN32 */
for (y = 0; y < height; y++) {
line = (y + yOffset) * iPtr->masterPtr->width;
for (x = 0; x < width; x++) {
modelPtr = alphaAr + ((line + x + xOffset) * 4);
alpha = modelPtr[3];
/*
* Ignore pixels that are fully transparent
*/
if (alpha) {
/*
* We could perhaps be more efficient than XGetPixel for 24
* and 32 bit displays, but this seems "fast enough".
*/
r = modelPtr[0];
g = modelPtr[1];
b = modelPtr[2];
if (alpha != 255) {
/*
* Only blend pixels that have some transparency
*/
unsigned char ra, ga, ba;
pixel = XGetPixel(bgImg, x, y);
ra = GetRValue(pixel);
ga = GetGValue(pixel);
ba = GetBValue(pixel);
unalpha = 255 - alpha; /* Calculate once. */
r = ALPHA_BLEND(ra, r, alpha, unalpha);
g = ALPHA_BLEND(ga, g, alpha, unalpha);
b = ALPHA_BLEND(ba, b, alpha, unalpha);
}
XPutPixel(bgImg, x, y, RGB(r, g, b));
}
}
}
#undef ALPHA_BLEND
}
#endif /* TKPUTIMAGE_CAN_BLEND */
/*
*----------------------------------------------------------------------
*
* TkImgPhotoDisplay --
*
* This function is invoked to draw a photo image.
*
* Results:
* None.
*
* Side effects:
* A portion of the image gets rendered in a pixmap or window.
*
*----------------------------------------------------------------------
*/
void
TkImgPhotoDisplay(
ClientData clientData, /* Pointer to PhotoInstance structure for
* instance to be displayed. */
Display *display, /* Display on which to draw image. */
Drawable drawable, /* Pixmap or window in which to draw image. */
int imageX, int imageY, /* Upper-left corner of region within image to
* draw. */
int width, int height, /* Dimensions of region within image to
* draw. */
int drawableX,int drawableY)/* Coordinates within drawable that correspond
* to imageX and imageY. */
{
PhotoInstance *instancePtr = clientData;
#ifndef TKPUTIMAGE_CAN_BLEND
XVisualInfo visInfo = instancePtr->visualInfo;
#endif
/*
* If there's no pixmap, it means that an error occurred while creating
* the image instance so it can't be displayed.
*/
if (instancePtr->pixels == None) {
return;
}
#ifdef TKPUTIMAGE_CAN_BLEND
/*
* If TkPutImage can handle RGBA Ximages directly there is
* no need to call XGetImage or to do the Porter-Duff compositing by hand.
*/
unsigned char *rgbaPixels = instancePtr->masterPtr->pix32;
XImage *photo = XCreateImage(display, NULL, 32, ZPixmap, 0, (char*)rgbaPixels,
(unsigned int)instancePtr->width,
(unsigned int)instancePtr->height,
0, (unsigned int)(4 * instancePtr->width));
TkPutImage(NULL, 0, display, drawable, instancePtr->gc,
photo, imageX, imageY, drawableX, drawableY,
(unsigned int) width, (unsigned int) height);
photo->data = NULL;
XDestroyImage(photo);
#else
if ((instancePtr->masterPtr->flags & COMPLEX_ALPHA)
&& visInfo.depth >= 15
&& (visInfo.c_class == DirectColor || visInfo.c_class == TrueColor)) {
Tk_ErrorHandler handler;
XImage *bgImg = NULL;
/*
* Create an error handler to suppress the case where the input was
* not properly constrained, which can cause an X error. [Bug 979239]
*/
handler = Tk_CreateErrorHandler(display, -1, -1, -1, NULL, NULL);
/*
* Pull the current background from the display to blend with
*/
bgImg = XGetImage(display, drawable, drawableX, drawableY,
(unsigned int)width, (unsigned int)height, AllPlanes, ZPixmap);
if (bgImg == NULL) {
Tk_DeleteErrorHandler(handler);
/* We failed to get the image, so draw without blending alpha.
* It's the best we can do.
*/
goto fallBack;
}
BlendComplexAlpha(bgImg, instancePtr, imageX, imageY, width, height);
/*
* Color info is unimportant as we only do this operation for depth >=
* 15.
*/
TkPutImage(NULL, 0, display, drawable, instancePtr->gc,
bgImg, 0, 0, drawableX, drawableY,
(unsigned int) width, (unsigned int) height);
XDestroyImage(bgImg);
Tk_DeleteErrorHandler(handler);
} else {
/*
* modelPtr->region describes which parts of the image contain valid
* data. We set this region as the clip mask for the gc, setting its
* origin appropriately, and use it when drawing the image.
*/
fallBack:
TkSetRegion(display, instancePtr->gc,
instancePtr->masterPtr->validRegion);
XSetClipOrigin(display, instancePtr->gc, drawableX - imageX,
drawableY - imageY);
XCopyArea(display, instancePtr->pixels, drawable, instancePtr->gc,
imageX, imageY, (unsigned) width, (unsigned) height,
drawableX, drawableY);
XSetClipMask(display, instancePtr->gc, None);
XSetClipOrigin(display, instancePtr->gc, 0, 0);
}
(void)XFlush(display);
#endif
}
/*
*----------------------------------------------------------------------
*
* TkImgPhotoFree --
*
* This function is called when a widget ceases to use a particular
* instance of an image. We don't actually get rid of the instance until
* later because we may be about to get this instance again.
*
* Results:
* None.
*
* Side effects:
* Internal data structures get cleaned up, later.
*
*----------------------------------------------------------------------
*/
void
TkImgPhotoFree(
ClientData clientData, /* Pointer to PhotoInstance structure for
* instance to be displayed. */
Display *display) /* Display containing window that used
* image. */
{
PhotoInstance *instancePtr = clientData;
ColorTable *colorPtr;
if (instancePtr->refCount-- > 1) {
return;
}
/*
* There are no more uses of the image within this widget. Decrement the
* count of live uses of its color table, so that its colors can be
* reclaimed if necessary, and set up an idle call to free the instance
* structure.
*/
colorPtr = instancePtr->colorTablePtr;
if (colorPtr != NULL) {
colorPtr->liveRefCount -= 1;
}
Tcl_DoWhenIdle(TkImgDisposeInstance, instancePtr);
}
/*
*----------------------------------------------------------------------
*
* TkImgPhotoInstanceSetSize --
*
* This function reallocates the instance pixmap and dithering error
* array for a photo instance, as necessary, to change the image's size
* to `width' x `height' pixels.
*
* Results:
* None.
*
* Side effects:
* Storage gets reallocated, here and in the X server.
*
*----------------------------------------------------------------------
*/
void
TkImgPhotoInstanceSetSize(
PhotoInstance *instancePtr) /* Instance whose size is to be changed. */
{
PhotoModel *modelPtr;
schar *newError, *errSrcPtr, *errDestPtr;
int h, offset;
XRectangle validBox;
Pixmap newPixmap;
modelPtr = instancePtr->masterPtr;
TkClipBox(modelPtr->validRegion, &validBox);
if ((instancePtr->width != modelPtr->width)
|| (instancePtr->height != modelPtr->height)
|| (instancePtr->pixels == None)) {
newPixmap = Tk_GetPixmap(instancePtr->display,
RootWindow(instancePtr->display,
instancePtr->visualInfo.screen),
(modelPtr->width > 0) ? modelPtr->width: 1,
(modelPtr->height > 0) ? modelPtr->height: 1,
instancePtr->visualInfo.depth);
if (!newPixmap) {
Tcl_Panic("Fail to create pixmap with Tk_GetPixmap in TkImgPhotoInstanceSetSize");
}
/*
* The following is a gross hack needed to properly support colormaps
* under Windows. Before the pixels can be copied to the pixmap, the
* relevent colormap must be associated with the drawable. Normally we
* can infer this association from the window that was used to create
* the pixmap. However, in this case we're using the root window, so
* we have to be more explicit.
*/
TkSetPixmapColormap(newPixmap, instancePtr->colormap);
if (instancePtr->pixels != None) {
/*
* Copy any common pixels from the old pixmap and free it.
*/
XCopyArea(instancePtr->display, instancePtr->pixels, newPixmap,
instancePtr->gc, validBox.x, validBox.y,
validBox.width, validBox.height, validBox.x, validBox.y);
Tk_FreePixmap(instancePtr->display, instancePtr->pixels);
}
instancePtr->pixels = newPixmap;
}
if ((instancePtr->width != modelPtr->width)
|| (instancePtr->height != modelPtr->height)
|| (instancePtr->error == NULL)) {
if (modelPtr->height > 0 && modelPtr->width > 0) {
/*
* TODO: use attemptckalloc() here once there is a strategy that
* will allow us to recover from failure. Right now, there's no
* such possibility.
*/
newError = ckalloc(modelPtr->height * modelPtr->width
* 3 * sizeof(schar));
/*
* Zero the new array so that we don't get bogus error values
* propagating into areas we dither later.
*/
if ((instancePtr->error != NULL)
&& ((instancePtr->width == modelPtr->width)
|| (validBox.width == modelPtr->width))) {
if (validBox.y > 0) {
memset(newError, 0, (size_t)
validBox.y * modelPtr->width * 3 * sizeof(schar));
}
h = validBox.y + validBox.height;
if (h < modelPtr->height) {
memset(newError + h*modelPtr->width*3, 0,
(size_t) (modelPtr->height - h)
* modelPtr->width * 3 * sizeof(schar));
}
} else {
memset(newError, 0, (size_t)
modelPtr->height * modelPtr->width *3*sizeof(schar));
}
} else {
newError = NULL;
}
if (instancePtr->error != NULL) {
/*
* Copy the common area over to the new array and free the old
* array.
*/
if (modelPtr->width == instancePtr->width) {
offset = validBox.y * modelPtr->width * 3;
memcpy(newError + offset, instancePtr->error + offset,
(size_t) (validBox.height
* modelPtr->width * 3 * sizeof(schar)));
} else if (validBox.width > 0 && validBox.height > 0) {
errDestPtr = newError +
(validBox.y * modelPtr->width + validBox.x) * 3;
errSrcPtr = instancePtr->error +
(validBox.y * instancePtr->width + validBox.x) * 3;
for (h = validBox.height; h > 0; --h) {
memcpy(errDestPtr, errSrcPtr,
validBox.width * 3 * sizeof(schar));
errDestPtr += modelPtr->width * 3;
errSrcPtr += instancePtr->width * 3;
}
}
ckfree(instancePtr->error);
}
instancePtr->error = newError;
}
instancePtr->width = modelPtr->width;
instancePtr->height = modelPtr->height;
}
/*
*----------------------------------------------------------------------
*
* IsValidPalette --
*
* This function is called to check whether a value given for the
* -palette option is valid for a particular instance of a photo image.
*
* Results:
* A boolean value: 1 if the palette is acceptable, 0 otherwise.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static int
IsValidPalette(
PhotoInstance *instancePtr, /* Instance to which the palette specification
* is to be applied. */
const char *palette) /* Palette specification string. */
{
int nRed, nGreen, nBlue, mono, numColors;
char *endp;
/*
* First parse the specification: it must be of the form %d or %d/%d/%d.
*/
nRed = strtol(palette, &endp, 10);
if ((endp == palette) || ((*endp != 0) && (*endp != '/'))
|| (nRed < 2) || (nRed > 256)) {
return 0;
}
if (*endp == 0) {
mono = 1;
nGreen = nBlue = nRed;
} else {
palette = endp + 1;
nGreen = strtol(palette, &endp, 10);
if ((endp == palette) || (*endp != '/') || (nGreen < 2)
|| (nGreen > 256)) {
return 0;
}
palette = endp + 1;
nBlue = strtol(palette, &endp, 10);
if ((endp == palette) || (*endp != 0) || (nBlue < 2)
|| (nBlue > 256)) {
return 0;
}
mono = 0;
}
switch (instancePtr->visualInfo.c_class) {
case DirectColor:
case TrueColor:
if ((nRed > (1 << CountBits(instancePtr->visualInfo.red_mask)))
|| (nGreen>(1<<CountBits(instancePtr->visualInfo.green_mask)))
|| (nBlue>(1<<CountBits(instancePtr->visualInfo.blue_mask)))) {
return 0;
}
break;
case PseudoColor:
case StaticColor:
numColors = nRed;
if (!mono) {
numColors *= nGreen * nBlue;
}
if (numColors > (1 << instancePtr->visualInfo.depth)) {
return 0;
}
break;
case GrayScale:
case StaticGray:
if (!mono || (nRed > (1 << instancePtr->visualInfo.depth))) {
return 0;
}
break;
}
return 1;
}
/*
*----------------------------------------------------------------------
*
* CountBits --
*
* This function counts how many bits are set to 1 in `mask'.
*
* Results:
* The integer number of bits.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static int
CountBits(
pixel mask) /* Value to count the 1 bits in. */
{
int n;
for (n=0 ; mask!=0 ; mask&=mask-1) {
n++;
}
return n;
}
/*
*----------------------------------------------------------------------
*
* GetColorTable --
*
* This function is called to allocate a table of colormap information
* for an instance of a photo image. Only one such table is allocated for
* all photo instances using the same display, colormap, palette and
* gamma values, so that the application need only request a set of
* colors from the X server once for all such photo widgets. This
* function maintains a hash table to find previously-allocated
* ColorTables.
*
* Results:
* None.
*
* Side effects:
* A new ColorTable may be allocated and placed in the hash table, and
* have colors allocated for it.
*
*----------------------------------------------------------------------
*/
static void
GetColorTable(
PhotoInstance *instancePtr) /* Instance needing a color table. */
{
ColorTable *colorPtr;
Tcl_HashEntry *entry;
ColorTableId id;
int isNew;
/*
* Look for an existing ColorTable in the hash table.
*/
memset(&id, 0, sizeof(id));
id.display = instancePtr->display;
id.colormap = instancePtr->colormap;
id.palette = instancePtr->palette;
id.gamma = instancePtr->gamma;
if (!imgPhotoColorHashInitialized) {
Tcl_InitHashTable(&imgPhotoColorHash, N_COLOR_HASH);
imgPhotoColorHashInitialized = 1;
}
entry = Tcl_CreateHashEntry(&imgPhotoColorHash, (char *) &id, &isNew);
if (!isNew) {
/*
* Re-use the existing entry.
*/
colorPtr = Tcl_GetHashValue(entry);
} else {
/*
* No color table currently available; need to make one.
*/
colorPtr = ckalloc(sizeof(ColorTable));
/*
* The following line of code should not normally be needed due to the
* assignment in the following line. However, it compensates for bugs
* in some compilers (HP, for example) where sizeof(ColorTable) is 24
* but the assignment only copies 20 bytes, leaving 4 bytes
* uninitialized; these cause problems when using the id for lookups
* in imgPhotoColorHash, and can result in core dumps.
*/
memset(&colorPtr->id, 0, sizeof(ColorTableId));
colorPtr->id = id;
Tk_PreserveColormap(colorPtr->id.display, colorPtr->id.colormap);
colorPtr->flags = 0;
colorPtr->refCount = 0;
colorPtr->liveRefCount = 0;
colorPtr->numColors = 0;
colorPtr->visualInfo = instancePtr->visualInfo;
colorPtr->pixelMap = NULL;
Tcl_SetHashValue(entry, colorPtr);
}
colorPtr->refCount++;
colorPtr->liveRefCount++;
instancePtr->colorTablePtr = colorPtr;
if (colorPtr->flags & DISPOSE_PENDING) {
Tcl_CancelIdleCall(DisposeColorTable, colorPtr);
colorPtr->flags &= ~DISPOSE_PENDING;
}
/*
* Allocate colors for this color table if necessary.
*/
if ((colorPtr->numColors == 0) && !(colorPtr->flags & BLACK_AND_WHITE)) {
AllocateColors(colorPtr);
}
}
/*
*----------------------------------------------------------------------
*
* FreeColorTable --
*
* This function is called when an instance ceases using a color table.
*
* Results:
* None.
*
* Side effects:
* If no other instances are using this color table, a when-idle handler
* is registered to free up the color table and the colors allocated for
* it.
*
*----------------------------------------------------------------------
*/
static void
FreeColorTable(
ColorTable *colorPtr, /* Pointer to the color table which is no
* longer required by an instance. */
int force) /* Force free to happen immediately. */
{
colorPtr->refCount--;
if (colorPtr->refCount > 0) {
return;
}
if (force) {
if (colorPtr->flags & DISPOSE_PENDING) {
Tcl_CancelIdleCall(DisposeColorTable, colorPtr);
colorPtr->flags &= ~DISPOSE_PENDING;
}
DisposeColorTable(colorPtr);
} else if (!(colorPtr->flags & DISPOSE_PENDING)) {
Tcl_DoWhenIdle(DisposeColorTable, colorPtr);
colorPtr->flags |= DISPOSE_PENDING;
}
}
/*
*----------------------------------------------------------------------
*
* AllocateColors --
*
* This function allocates the colors required by a color table, and sets
* up the fields in the color table data structure which are used in
* dithering.
*
* Results:
* None.
*
* Side effects:
* Colors are allocated from the X server. Fields in the color table data
* structure are updated.
*
*----------------------------------------------------------------------
*/
static void
AllocateColors(
ColorTable *colorPtr) /* Pointer to the color table requiring colors
* to be allocated. */
{
int i, r, g, b, rMult, mono;
int numColors, nRed, nGreen, nBlue;
double fr, fg, fb, igam;
XColor *colors;
unsigned long *pixels;
/*
* 16-bit intensity value for i/n of full intensity.
*/
#define CFRAC(i, n) ((i) * 65535 / (n))
/* As for CFRAC, but apply exponent of g. */
#define CGFRAC(i, n, g) ((int)(65535 * pow((double)(i) / (n), (g))))
/*
* First parse the palette specification to get the required number of
* shades of each primary.
*/
mono = sscanf(colorPtr->id.palette, "%d/%d/%d", &nRed, &nGreen, &nBlue)
<= 1;
igam = 1.0 / colorPtr->id.gamma;
/*
* Each time around this loop, we reduce the number of colors we're trying
* to allocate until we succeed in allocating all of the colors we need.
*/
for (;;) {
/*
* If we are using 1 bit/pixel, we don't need to allocate any colors
* (we just use the foreground and background colors in the GC).
*/
if (mono && (nRed <= 2)) {
colorPtr->flags |= BLACK_AND_WHITE;
return;
}
/*
* Calculate the RGB coordinates of the colors we want to allocate and
* store them in *colors.
*/
if ((colorPtr->visualInfo.c_class == DirectColor)
|| (colorPtr->visualInfo.c_class == TrueColor)) {
/*
* Direct/True Color: allocate shades of red, green, blue
* independently.
*/
if (mono) {
numColors = nGreen = nBlue = nRed;
} else {
numColors = MAX(MAX(nRed, nGreen), nBlue);
}
colors = ckalloc(numColors * sizeof(XColor));
for (i = 0; i < numColors; ++i) {
if (igam == 1.0) {
colors[i].red = CFRAC(i, nRed - 1);
colors[i].green = CFRAC(i, nGreen - 1);
colors[i].blue = CFRAC(i, nBlue - 1);
} else {
colors[i].red = CGFRAC(i, nRed - 1, igam);
colors[i].green = CGFRAC(i, nGreen - 1, igam);
colors[i].blue = CGFRAC(i, nBlue - 1, igam);
}
}
} else {
/*
* PseudoColor, StaticColor, GrayScale or StaticGray visual: we
* have to allocate each color in the color cube separately.
*/
numColors = (mono) ? nRed: (nRed * nGreen * nBlue);
colors = ckalloc(numColors * sizeof(XColor));
if (!mono) {
/*
* Color display using a PseudoColor or StaticColor visual.
*/
i = 0;
for (r = 0; r < nRed; ++r) {
for (g = 0; g < nGreen; ++g) {
for (b = 0; b < nBlue; ++b) {
if (igam == 1.0) {
colors[i].red = CFRAC(r, nRed - 1);
colors[i].green = CFRAC(g, nGreen - 1);
colors[i].blue = CFRAC(b, nBlue - 1);
} else {
colors[i].red = CGFRAC(r, nRed - 1, igam);
colors[i].green = CGFRAC(g, nGreen - 1, igam);
colors[i].blue = CGFRAC(b, nBlue - 1, igam);
}
i++;
}
}
}
} else {
/*
* Monochrome display - allocate the shades of gray we want.
*/
for (i = 0; i < numColors; ++i) {
if (igam == 1.0) {
r = CFRAC(i, numColors - 1);
} else {
r = CGFRAC(i, numColors - 1, igam);
}
colors[i].red = colors[i].green = colors[i].blue = r;
}
}
}
/*
* Now try to allocate the colors we've calculated.
*/
pixels = ckalloc(numColors * sizeof(unsigned long));
for (i = 0; i < numColors; ++i) {
if (!XAllocColor(colorPtr->id.display, colorPtr->id.colormap,
&colors[i])) {
/*
* Can't get all the colors we want in the default colormap;
* first try freeing colors from other unused color tables.
*/
if (!ReclaimColors(&colorPtr->id, numColors - i)
|| !XAllocColor(colorPtr->id.display,
colorPtr->id.colormap, &colors[i])) {
/*
* Still can't allocate the color.
*/
break;
}
}
pixels[i] = colors[i].pixel;
}
/*
* If we didn't get all of the colors, reduce the resolution of the
* color cube, free the ones we got, and try again.
*/
if (i >= numColors) {
break;
}
XFreeColors(colorPtr->id.display, colorPtr->id.colormap, pixels, i, 0);
ckfree(colors);
ckfree(pixels);
if (!mono) {
if ((nRed == 2) && (nGreen == 2) && (nBlue == 2)) {
/*
* Fall back to 1-bit monochrome display.
*/
mono = 1;
} else {
/*
* Reduce the number of shades of each primary to about 3/4 of
* the previous value. This should reduce the total number of
* colors required to about half the previous value for
* PseudoColor displays.
*/
nRed = (nRed * 3 + 2) / 4;
nGreen = (nGreen * 3 + 2) / 4;
nBlue = (nBlue * 3 + 2) / 4;
}
} else {
/*
* Reduce the number of shades of gray to about 1/2.
*/
nRed = nRed / 2;
}
}
/*
* We have allocated all of the necessary colors: fill in various fields
* of the ColorTable record.
*/
if (!mono) {
colorPtr->flags |= COLOR_WINDOW;
/*
* The following is a hairy hack. We only want to index into the
* pixelMap on colormap displays. However, if the display is on
* Windows, then we actually want to store the index not the value
* since we will be passing the color table into the TkPutImage call.
*/
#ifndef _WIN32
if ((colorPtr->visualInfo.c_class != DirectColor)
&& (colorPtr->visualInfo.c_class != TrueColor)) {
colorPtr->flags |= MAP_COLORS;
}
#endif /* _WIN32 */
}
colorPtr->numColors = numColors;
colorPtr->pixelMap = pixels;
/*
* Set up quantization tables for dithering.
*/
rMult = nGreen * nBlue;
for (i = 0; i < 256; ++i) {
r = (i * (nRed - 1) + 127) / 255;
if (mono) {
fr = (double) colors[r].red / 65535.0;
if (colorPtr->id.gamma != 1.0 ) {
fr = pow(fr, colorPtr->id.gamma);
}
colorPtr->colorQuant[0][i] = (int)(fr * 255.99);
colorPtr->redValues[i] = colors[r].pixel;
} else {
g = (i * (nGreen - 1) + 127) / 255;
b = (i * (nBlue - 1) + 127) / 255;
if ((colorPtr->visualInfo.c_class == DirectColor)
|| (colorPtr->visualInfo.c_class == TrueColor)) {
colorPtr->redValues[i] =
colors[r].pixel & colorPtr->visualInfo.red_mask;
colorPtr->greenValues[i] =
colors[g].pixel & colorPtr->visualInfo.green_mask;
colorPtr->blueValues[i] =
colors[b].pixel & colorPtr->visualInfo.blue_mask;
} else {
r *= rMult;
g *= nBlue;
colorPtr->redValues[i] = r;
colorPtr->greenValues[i] = g;
colorPtr->blueValues[i] = b;
}
fr = (double) colors[r].red / 65535.0;
fg = (double) colors[g].green / 65535.0;
fb = (double) colors[b].blue / 65535.0;
if (colorPtr->id.gamma != 1.0) {
fr = pow(fr, colorPtr->id.gamma);
fg = pow(fg, colorPtr->id.gamma);
fb = pow(fb, colorPtr->id.gamma);
}
colorPtr->colorQuant[0][i] = (int)(fr * 255.99);
colorPtr->colorQuant[1][i] = (int)(fg * 255.99);
colorPtr->colorQuant[2][i] = (int)(fb * 255.99);
}
}
ckfree(colors);
}
/*
*----------------------------------------------------------------------
*
* DisposeColorTable --
*
* Release a color table and its associated resources.
*
* Results:
* None.
*
* Side effects:
* The colors in the argument color table are freed, as is the color
* table structure itself. The color table is removed from the hash table
* which is used to locate color tables.
*
*----------------------------------------------------------------------
*/
static void
DisposeColorTable(
ClientData clientData) /* Pointer to the ColorTable whose
* colors are to be released. */
{
ColorTable *colorPtr = clientData;
Tcl_HashEntry *entry;
if (colorPtr->pixelMap != NULL) {
if (colorPtr->numColors > 0) {
XFreeColors(colorPtr->id.display, colorPtr->id.colormap,
colorPtr->pixelMap, colorPtr->numColors, 0);
Tk_FreeColormap(colorPtr->id.display, colorPtr->id.colormap);
}
ckfree(colorPtr->pixelMap);
}
entry = Tcl_FindHashEntry(&imgPhotoColorHash, (char *) &colorPtr->id);
if (entry == NULL) {
Tcl_Panic("DisposeColorTable couldn't find hash entry");
}
Tcl_DeleteHashEntry(entry);
ckfree(colorPtr);
}
/*
*----------------------------------------------------------------------
*
* ReclaimColors --
*
* This function is called to try to free up colors in the colormap used
* by a color table. It looks for other color tables with the same
* colormap and with a zero live reference count, and frees their colors.
* It only does so if there is the possibility of freeing up at least
* `numColors' colors.
*
* Results:
* The return value is TRUE if any colors were freed, FALSE otherwise.
*
* Side effects:
* ColorTables which are not currently in use may lose their color
* allocations.
*
*----------------------------------------------------------------------
*/
static int
ReclaimColors(
ColorTableId *id, /* Pointer to information identifying
* the color table which needs more colors. */
int numColors) /* Number of colors required. */
{
Tcl_HashSearch srch;
Tcl_HashEntry *entry;
ColorTable *colorPtr;
int nAvail = 0;
/*
* First scan through the color hash table to get an upper bound on how
* many colors we might be able to free.
*/
entry = Tcl_FirstHashEntry(&imgPhotoColorHash, &srch);
while (entry != NULL) {
colorPtr = Tcl_GetHashValue(entry);
if ((colorPtr->id.display == id->display)
&& (colorPtr->id.colormap == id->colormap)
&& (colorPtr->liveRefCount == 0 )&& (colorPtr->numColors != 0)
&& ((colorPtr->id.palette != id->palette)
|| (colorPtr->id.gamma != id->gamma))) {
/*
* We could take this guy's colors off him.
*/
nAvail += colorPtr->numColors;
}
entry = Tcl_NextHashEntry(&srch);
}
/*
* nAvail is an (over)estimate of the number of colors we could free.
*/
if (nAvail < numColors) {
return 0;
}
/*
* Scan through a second time freeing colors.
*/
entry = Tcl_FirstHashEntry(&imgPhotoColorHash, &srch);
while ((entry != NULL) && (numColors > 0)) {
colorPtr = Tcl_GetHashValue(entry);
if ((colorPtr->id.display == id->display)
&& (colorPtr->id.colormap == id->colormap)
&& (colorPtr->liveRefCount == 0) && (colorPtr->numColors != 0)
&& ((colorPtr->id.palette != id->palette)
|| (colorPtr->id.gamma != id->gamma))) {
/*
* Free the colors that this ColorTable has.
*/
XFreeColors(colorPtr->id.display, colorPtr->id.colormap,
colorPtr->pixelMap, colorPtr->numColors, 0);
numColors -= colorPtr->numColors;
colorPtr->numColors = 0;
ckfree(colorPtr->pixelMap);
colorPtr->pixelMap = NULL;
}
entry = Tcl_NextHashEntry(&srch);
}
return 1; /* We freed some colors. */
}
/*
*----------------------------------------------------------------------
*
* TkImgDisposeInstance --
*
* This function is called to finally free up an instance of a photo
* image which is no longer required.
*
* Results:
* None.
*
* Side effects:
* The instance data structure and the resources it references are freed.
*
*----------------------------------------------------------------------
*/
void
TkImgDisposeInstance(
ClientData clientData) /* Pointer to the instance whose resources are
* to be released. */
{
PhotoInstance *instancePtr = clientData;
PhotoInstance *prevPtr;
if (instancePtr->pixels != None) {
Tk_FreePixmap(instancePtr->display, instancePtr->pixels);
}
if (instancePtr->gc != NULL) {
Tk_FreeGC(instancePtr->display, instancePtr->gc);
}
if (instancePtr->imagePtr != NULL) {
XDestroyImage(instancePtr->imagePtr);
}
if (instancePtr->error != NULL) {
ckfree(instancePtr->error);
}
if (instancePtr->colorTablePtr != NULL) {
FreeColorTable(instancePtr->colorTablePtr, 1);
}
if (instancePtr->masterPtr->instancePtr == instancePtr) {
instancePtr->masterPtr->instancePtr = instancePtr->nextPtr;
} else {
for (prevPtr = instancePtr->masterPtr->instancePtr;
prevPtr->nextPtr != instancePtr; prevPtr = prevPtr->nextPtr) {
/* Empty loop body. */
}
prevPtr->nextPtr = instancePtr->nextPtr;
}
Tk_FreeColormap(instancePtr->display, instancePtr->colormap);
ckfree(instancePtr);
}
/*
*----------------------------------------------------------------------
*
* TkImgDitherInstance --
*
* This function is called to update an area of an instance's pixmap by
* dithering the corresponding area of the model.
*
* Results:
* None.
*
* Side effects:
* The instance's pixmap gets updated.
*
*----------------------------------------------------------------------
*/
void
TkImgDitherInstance(
PhotoInstance *instancePtr, /* The instance to be updated. */
int xStart, int yStart, /* Coordinates of the top-left pixel in the
* block to be dithered. */
int width, int height) /* Dimensions of the block to be dithered. */
{
PhotoModel *modelPtr = instancePtr->masterPtr;
ColorTable *colorPtr = instancePtr->colorTablePtr;
XImage *imagePtr;
int nLines, bigEndian, i, c, x, y, xEnd, doDithering = 1;
int bitsPerPixel, bytesPerLine, lineLength;
unsigned char *srcLinePtr;
schar *errLinePtr;
pixel firstBit, word, mask;
/*
* Turn dithering off in certain cases where it is not needed (TrueColor,
* DirectColor with many colors).
*/
if ((colorPtr->visualInfo.c_class == DirectColor)
|| (colorPtr->visualInfo.c_class == TrueColor)) {
int nRed, nGreen, nBlue, result;
result = sscanf(colorPtr->id.palette, "%d/%d/%d", &nRed,
&nGreen, &nBlue);
if ((nRed >= 256)
&& ((result == 1) || ((nGreen >= 256) && (nBlue >= 256)))) {
doDithering = 0;
}
}
/*
* First work out how many lines to do at a time, then how many bytes
* we'll need for pixel storage, and allocate it.
*/
nLines = (MAX_PIXELS + width - 1) / width;
if (nLines < 1) {
nLines = 1;
}
if (nLines > height ) {
nLines = height;
}
imagePtr = instancePtr->imagePtr;
if (imagePtr == NULL) {
return; /* We must be really tight on memory. */
}
bitsPerPixel = imagePtr->bits_per_pixel;
bytesPerLine = ((bitsPerPixel * width + 31) >> 3) & ~3;
imagePtr->width = width;
imagePtr->height = nLines;
imagePtr->bytes_per_line = bytesPerLine;
/*
* TODO: use attemptckalloc() here once we have some strategy for
* recovering from the failure.
*/
imagePtr->data = ckalloc(imagePtr->bytes_per_line * nLines);
bigEndian = imagePtr->bitmap_bit_order == MSBFirst;
firstBit = bigEndian? (1 << (imagePtr->bitmap_unit - 1)): 1;
lineLength = modelPtr->width * 3;
srcLinePtr = modelPtr->pix32 + (yStart * modelPtr->width + xStart) * 4;
errLinePtr = instancePtr->error + yStart * lineLength + xStart * 3;
xEnd = xStart + width;
/*
* Loop over the image, doing at most nLines lines before updating the
* screen image.
*/
for (; height > 0; height -= nLines) {
unsigned char *dstLinePtr = (unsigned char *) imagePtr->data;
int yEnd;
if (nLines > height) {
nLines = height;
}
yEnd = yStart + nLines;
for (y = yStart; y < yEnd; ++y) {
unsigned char *srcPtr = srcLinePtr;
schar *errPtr = errLinePtr;
unsigned char *destBytePtr = dstLinePtr;
pixel *destLongPtr = (pixel *) dstLinePtr;
if (colorPtr->flags & COLOR_WINDOW) {
/*
* Color window. We dither the three components independently,
* using Floyd-Steinberg dithering, which propagates errors
* from the quantization of pixels to the pixels below and to
* the right.
*/
for (x = xStart; x < xEnd; ++x) {
int col[3];
if (doDithering) {
for (i = 0; i < 3; ++i) {
/*
* Compute the error propagated into this pixel
* for this component. If e[x,y] is the array of
* quantization error values, we compute
* 7/16 * e[x-1,y] + 1/16 * e[x-1,y-1]
* + 5/16 * e[x,y-1] + 3/16 * e[x+1,y-1]
* and round it to an integer.
*
* The expression ((c + 2056) >> 4) - 128 computes
* round(c / 16), and works correctly on machines
* without a sign-extending right shift.
*/
c = (x > 0) ? errPtr[-3] * 7: 0;
if (y > 0) {
if (x > 0) {
c += errPtr[-lineLength-3];
}
c += errPtr[-lineLength] * 5;
if ((x + 1) < modelPtr->width) {
c += errPtr[-lineLength+3] * 3;
}
}
/*
* Add the propagated error to the value of this
* component, quantize it, and store the
* quantization error.
*/
c = ((c + 2056) >> 4) - 128 + *srcPtr++;
if (c < 0) {
c = 0;
} else if (c > 255) {
c = 255;
}
col[i] = colorPtr->colorQuant[i][c];
*errPtr++ = c - col[i];
}
} else {
/*
* Output is virtually continuous in this case, so
* don't bother dithering.
*/
col[0] = *srcPtr++;
col[1] = *srcPtr++;
col[2] = *srcPtr++;
}
srcPtr++;
/*
* Translate the quantized component values into an X
* pixel value, and store it in the image.
*/
i = colorPtr->redValues[col[0]]
+ colorPtr->greenValues[col[1]]
+ colorPtr->blueValues[col[2]];
if (colorPtr->flags & MAP_COLORS) {
i = colorPtr->pixelMap[i];
}
switch (bitsPerPixel) {
case NBBY:
*destBytePtr++ = i;
break;
#ifndef _WIN32
/*
* This case is not valid for Windows because the
* image format is different from the pixel format in
* Win32. Eventually we need to fix the image code in
* Tk to use the Windows native image ordering. This
* would speed up the image code for all of the common
* sizes.
*/
case NBBY * sizeof(pixel):
*destLongPtr++ = i;
break;
#endif
default:
XPutPixel(imagePtr, x - xStart, y - yStart,
(unsigned) i);
}
}
} else if (bitsPerPixel > 1) {
/*
* Multibit monochrome window. The operation here is similar
* to the color window case above, except that there is only
* one component. If the model image is in color, use the
* luminance computed as
* 0.344 * red + 0.5 * green + 0.156 * blue.
*/
for (x = xStart; x < xEnd; ++x) {
c = (x > 0) ? errPtr[-1] * 7: 0;
if (y > 0) {
if (x > 0) {
c += errPtr[-lineLength-1];
}
c += errPtr[-lineLength] * 5;
if (x + 1 < modelPtr->width) {
c += errPtr[-lineLength+1] * 3;
}
}
c = ((c + 2056) >> 4) - 128;
if (modelPtr->flags & COLOR_IMAGE) {
c += (unsigned) (srcPtr[0] * 11 + srcPtr[1] * 16
+ srcPtr[2] * 5 + 16) >> 5;
} else {
c += srcPtr[0];
}
srcPtr += 4;
if (c < 0) {
c = 0;
} else if (c > 255) {
c = 255;
}
i = colorPtr->colorQuant[0][c];
*errPtr++ = c - i;
i = colorPtr->redValues[i];
switch (bitsPerPixel) {
case NBBY:
*destBytePtr++ = i;
break;
#ifndef _WIN32
/*
* This case is not valid for Windows because the
* image format is different from the pixel format in
* Win32. Eventually we need to fix the image code in
* Tk to use the Windows native image ordering. This
* would speed up the image code for all of the common
* sizes.
*/
case NBBY * sizeof(pixel):
*destLongPtr++ = i;
break;
#endif
default:
XPutPixel(imagePtr, x - xStart, y - yStart,
(unsigned) i);
}
}
} else {
/*
* 1-bit monochrome window. This is similar to the multibit
* monochrome case above, except that the quantization is
* simpler (we only have black = 0 and white = 255), and we
* produce an XY-Bitmap.
*/
word = 0;
mask = firstBit;
for (x = xStart; x < xEnd; ++x) {
/*
* If we have accumulated a whole word, store it in the
* image and start a new word.
*/
if (mask == 0) {
*destLongPtr++ = word;
mask = firstBit;
word = 0;
}
c = (x > 0) ? errPtr[-1] * 7: 0;
if (y > 0) {
if (x > 0) {
c += errPtr[-lineLength-1];
}
c += errPtr[-lineLength] * 5;
if (x + 1 < modelPtr->width) {
c += errPtr[-lineLength+1] * 3;
}
}
c = ((c + 2056) >> 4) - 128;
if (modelPtr->flags & COLOR_IMAGE) {
c += (unsigned)(srcPtr[0] * 11 + srcPtr[1] * 16
+ srcPtr[2] * 5 + 16) >> 5;
} else {
c += srcPtr[0];
}
srcPtr += 4;
if (c < 0) {
c = 0;
} else if (c > 255) {
c = 255;
}
if (c >= 128) {
word |= mask;
*errPtr++ = c - 255;
} else {
*errPtr++ = c;
}
mask = bigEndian? (mask >> 1): (mask << 1);
}
*destLongPtr = word;
}
srcLinePtr += modelPtr->width * 4;
errLinePtr += lineLength;
dstLinePtr += bytesPerLine;
}
/*
* Update the pixmap for this instance with the block of pixels that
* we have just computed.
*/
TkPutImage(colorPtr->pixelMap, colorPtr->numColors,
instancePtr->display, instancePtr->pixels,
instancePtr->gc, imagePtr, 0, 0, xStart, yStart,
(unsigned) width, (unsigned) nLines);
yStart = yEnd;
}
ckfree(imagePtr->data);
imagePtr->data = NULL;
}
/*
*----------------------------------------------------------------------
*
* TkImgResetDither --
*
* This function is called to eliminate the content of a photo instance's
* dither error buffer. It's called when the overall image is blanked.
*
* Results:
* None.
*
* Side effects:
* The instance's dither buffer gets cleared.
*
*----------------------------------------------------------------------
*/
void
TkImgResetDither(
PhotoInstance *instancePtr)
{
if (instancePtr->error) {
memset(instancePtr->error, 0,
/*(size_t)*/ (instancePtr->masterPtr->width
* instancePtr->masterPtr->height * 3 * sizeof(schar)));
}
}
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/
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