void
nsPNGDecoder::row_callback(png_structp png_ptr, png_bytep new_row,
png_uint_32 row_num, int pass)
{
/* libpng comments:
*
* this function is called for every row in the image. If the
* image is interlacing, and you turned on the interlace handler,
* this function will be called for every row in every pass.
* Some of these rows will not be changed from the previous pass.
* When the row is not changed, the new_row variable will be
* nullptr. The rows and passes are called in order, so you don't
* really need the row_num and pass, but I'm supplying them
* because it may make your life easier.
*
* For the non-nullptr rows of interlaced images, you must call
* png_progressive_combine_row() passing in the row and the
* old row. You can call this function for nullptr rows (it will
* just return) and for non-interlaced images (it just does the
* memcpy for you) if it will make the code easier. Thus, you
* can just do this for all cases:
*
* png_progressive_combine_row(png_ptr, old_row, new_row);
*
* where old_row is what was displayed for previous rows. Note
* that the first pass (pass == 0 really) will completely cover
* the old row, so the rows do not have to be initialized. After
* the first pass (and only for interlaced images), you will have
* to pass the current row, and the function will combine the
* old row and the new row.
*/
nsPNGDecoder* decoder =
static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
// skip this frame
if (decoder->mFrameIsHidden) {
return;
}
if (row_num >= (png_uint_32) decoder->mFrameRect.height) {
return;
}
if (new_row) {
int32_t width = decoder->mFrameRect.width;
uint32_t iwidth = decoder->mFrameRect.width;
png_bytep line = new_row;
if (decoder->interlacebuf) {
line = decoder->interlacebuf + (row_num * decoder->mChannels * width);
png_progressive_combine_row(png_ptr, line, new_row);
}
uint32_t bpr = width * sizeof(uint32_t);
uint32_t* cptr32 = (uint32_t*)(decoder->mImageData + (row_num*bpr));
if (decoder->mTransform) {
if (decoder->mCMSLine) {
qcms_transform_data(decoder->mTransform, line, decoder->mCMSLine,
iwidth);
// copy alpha over
uint32_t channels = decoder->mChannels;
if (channels == 2 || channels == 4) {
for (uint32_t i = 0; i < iwidth; i++)
decoder->mCMSLine[4 * i + 3] = line[channels * i + channels - 1];
}
line = decoder->mCMSLine;
} else {
qcms_transform_data(decoder->mTransform, line, line, iwidth);
}
}
switch (decoder->format) {
case gfx::SurfaceFormat::B8G8R8X8: {
// counter for while() loops below
uint32_t idx = iwidth;
// copy as bytes until source pointer is 32-bit-aligned
for (; (NS_PTR_TO_UINT32(line) & 0x3) && idx; --idx) {
*cptr32++ = gfxPackedPixel(0xFF, line[0], line[1], line[2]);
line += 3;
}
// copy pixels in blocks of 4
while (idx >= 4) {
GFX_BLOCK_RGB_TO_FRGB(line, cptr32);
idx -= 4;
line += 12;
cptr32 += 4;
}
// copy remaining pixel(s)
while (idx--) {
// 32-bit read of final pixel will exceed buffer, so read bytes
*cptr32++ = gfxPackedPixel(0xFF, line[0], line[1], line[2]);
line += 3;
}
}
break;
case gfx::SurfaceFormat::B8G8R8A8: {
if (!decoder->mDisablePremultipliedAlpha) {
for (uint32_t x=width; x>0; --x) {
*cptr32++ = gfxPackedPixel(line[3], line[0], line[1], line[2]);
line += 4;
}
} else {
for (uint32_t x=width; x>0; --x) {
*cptr32++ = gfxPackedPixelNoPreMultiply(line[3], line[0], line[1],
line[2]);
line += 4;
}
}
}
break;
default:
png_longjmp(decoder->mPNG, 1);
}
if (decoder->mNumFrames <= 1) {
// Only do incremental image display for the first frame
// XXXbholley - this check should be handled in the superclass
nsIntRect r(0, row_num, width, 1);
decoder->PostInvalidation(r);
}
}
}
void
ReadPixelsIntoImageSurface(GLContext* gl, gfxImageSurface* dest) {
gl->MakeCurrent();
MOZ_ASSERT(dest->GetSize() != gfxIntSize(0, 0));
/* gfxImageFormat::ARGB32:
* RGBA+UByte: be[RGBA], le[ABGR]
* RGBA+UInt: le[RGBA]
* BGRA+UInt: le[BGRA]
* BGRA+UIntRev: le[ARGB]
*
* gfxImageFormat::RGB16_565:
* RGB+UShort: le[rrrrrggg,gggbbbbb]
*/
bool hasAlpha = dest->Format() == gfxImageFormat::ARGB32;
int destPixelSize;
GLenum destFormat;
GLenum destType;
switch (dest->Format()) {
case gfxImageFormat::RGB24: // XRGB
case gfxImageFormat::ARGB32:
destPixelSize = 4;
// Needs host (little) endian ARGB.
destFormat = LOCAL_GL_BGRA;
destType = LOCAL_GL_UNSIGNED_INT_8_8_8_8_REV;
break;
case gfxImageFormat::RGB16_565:
destPixelSize = 2;
destFormat = LOCAL_GL_RGB;
destType = LOCAL_GL_UNSIGNED_SHORT_5_6_5_REV;
break;
default:
MOZ_CRASH("Bad format.");
}
MOZ_ASSERT(dest->Stride() == dest->Width() * destPixelSize);
GLenum readFormat = destFormat;
GLenum readType = destType;
bool needsTempSurf = !GetActualReadFormats(gl,
destFormat, destType,
readFormat, readType);
nsAutoPtr<gfxImageSurface> tempSurf;
gfxImageSurface* readSurf = nullptr;
int readPixelSize = 0;
if (needsTempSurf) {
if (gl->DebugMode()) {
NS_WARNING("Needing intermediary surface for ReadPixels. This will be slow!");
}
SurfaceFormat readFormatGFX;
switch (readFormat) {
case LOCAL_GL_RGBA:
case LOCAL_GL_BGRA: {
readFormatGFX = hasAlpha ? SurfaceFormat::B8G8R8A8
: SurfaceFormat::B8G8R8X8;
break;
}
case LOCAL_GL_RGB: {
MOZ_ASSERT(readPixelSize == 2);
MOZ_ASSERT(readType == LOCAL_GL_UNSIGNED_SHORT_5_6_5_REV);
readFormatGFX = SurfaceFormat::R5G6B5;
break;
}
default: {
MOZ_CRASH("Bad read format.");
}
}
switch (readType) {
case LOCAL_GL_UNSIGNED_BYTE: {
MOZ_ASSERT(readFormat == LOCAL_GL_RGBA);
readPixelSize = 4;
break;
}
case LOCAL_GL_UNSIGNED_INT_8_8_8_8_REV: {
MOZ_ASSERT(readFormat == LOCAL_GL_BGRA);
readPixelSize = 4;
break;
}
case LOCAL_GL_UNSIGNED_SHORT_5_6_5_REV: {
MOZ_ASSERT(readFormat == LOCAL_GL_RGB);
readPixelSize = 2;
break;
}
default: {
MOZ_CRASH("Bad read type.");
}
}
tempSurf = new gfxImageSurface(dest->GetSize(),
SurfaceFormatToImageFormat(readFormatGFX),
false);
readSurf = tempSurf;
} else {
readPixelSize = destPixelSize;
readSurf = dest;
}
MOZ_ASSERT(readPixelSize);
GLint currentPackAlignment = 0;
gl->fGetIntegerv(LOCAL_GL_PACK_ALIGNMENT, ¤tPackAlignment);
if (currentPackAlignment != readPixelSize)
gl->fPixelStorei(LOCAL_GL_PACK_ALIGNMENT, readPixelSize);
GLsizei width = dest->Width();
GLsizei height = dest->Height();
readSurf->Flush();
gl->fReadPixels(0, 0,
width, height,
readFormat, readType,
readSurf->Data());
readSurf->MarkDirty();
if (currentPackAlignment != readPixelSize)
gl->fPixelStorei(LOCAL_GL_PACK_ALIGNMENT, currentPackAlignment);
if (readSurf != dest) {
MOZ_ASSERT(readFormat == LOCAL_GL_RGBA);
MOZ_ASSERT(readType == LOCAL_GL_UNSIGNED_BYTE);
// So we just copied in RGBA in big endian, or le: 0xAABBGGRR.
// We want 0xAARRGGBB, so swap R and B:
dest->Flush();
RefPtr<DataSourceSurface> readDSurf =
Factory::CreateWrappingDataSourceSurface(readSurf->Data(),
readSurf->Stride(),
ToIntSize(readSurf->GetSize()),
ImageFormatToSurfaceFormat(readSurf->Format()));
SwapRAndBComponents(readDSurf);
dest->MarkDirty();
gfxContext ctx(dest);
ctx.SetOperator(gfxContext::OPERATOR_SOURCE);
ctx.SetSource(readSurf);
ctx.Paint();
}
// Check if GL is giving back 1.0 alpha for
// RGBA reads to RGBA images from no-alpha buffers.
#ifdef XP_MACOSX
if (gl->WorkAroundDriverBugs() &&
gl->Vendor() == gl::GLVendor::NVIDIA &&
dest->Format() == gfxImageFormat::ARGB32 &&
width && height)
{
GLint alphaBits = 0;
gl->fGetIntegerv(LOCAL_GL_ALPHA_BITS, &alphaBits);
if (!alphaBits) {
const uint32_t alphaMask = gfxPackedPixelNoPreMultiply(0xff,0,0,0);
dest->Flush();
uint32_t* itr = (uint32_t*)dest->Data();
uint32_t testPixel = *itr;
if ((testPixel & alphaMask) != alphaMask) {
// We need to set the alpha channel to 1.0 manually.
uint32_t* itrEnd = itr + width*height; // Stride is guaranteed to be width*4.
for (; itr != itrEnd; itr++) {
*itr |= alphaMask;
}
}
dest->MarkDirty();
}
}
#endif
}