void GIFImageDecoder::initFrameBuffer(RGBA32Buffer& buffer,
RGBA32Buffer* previousBuffer,
bool compositeWithPreviousFrame)
{
// Initialize the frame rect in our buffer.
IntRect frameRect(m_reader->frameXOffset(), m_reader->frameYOffset(),
m_reader->frameWidth(), m_reader->frameHeight());
buffer.setRect(frameRect);
bool isSubRect = (frameRect.x() > 0 || frameRect.y() > 0 ||
frameRect.width() < m_size.width() ||
frameRect.height() < m_size.height());
// Let's resize our buffer now to the correct width/height and then
// initialize portions of it if needed.
RGBA32Array& bytes = buffer.bytes();
// If the disposal method of the previous frame said to stick around, then we need
// to copy that frame into our frame. We also dont want to have any impact on
// anything outside our frame's rect, so if we don't overlay the entire image,
// then also composite with the previous frame.
if (previousBuffer && (compositeWithPreviousFrame || isSubRect)) {
bytes = previousBuffer->bytes();
buffer.ensureHeight(m_size.height());
buffer.setHasAlpha(previousBuffer->hasAlpha());
}
else // Resize to the width and height of the image.
bytes.resize(m_size.width() * m_size.height());
if (isSubRect) {
// We need to go ahead and initialize the first frame to make sure
// that areas outside the subrect start off transparent.
if (!previousBuffer) {
bytes.fill(0);
buffer.setHasAlpha(true);
} else if (!compositeWithPreviousFrame) {
// Now this is an interesting case. In the case where we fill
// the entire image, we effectively do a full clear of the image (and thus
// don't have to initialize anything in our buffer).
//
// However in the case where we only fill a piece of the image, two problems occur:
// (1) We need to wipe out the area occupied by the previous frame, which
// could also have been a subrect.
// (2) Anything outside the previous frame's rect *and* outside our current
// frame's rect should be left alone.
// We have handled (2) by just initializing our buffer from the previous frame.
// Our subrect will correctly overwrite the previous frame's contents as we
// decode rows. However that still leaves the problem of having to wipe out
// the area occupied by the previous frame that does not overlap with
// the new frame.
if (previousBuffer->rect() != frameRect) {
// We have to clear out the entire previous subframe.
bool sawAlpha = buffer.hasAlpha();
IntRect prevRect = previousBuffer->rect();
unsigned end = prevRect.y() + prevRect.height();
unsigned* src;
for (unsigned i = prevRect.y(); i < end; i++) {
unsigned* curr = buffer.bytes().data() + (i * m_size.width() + prevRect.x());
unsigned* end = curr + prevRect.width();
while (curr != end) {
if (!sawAlpha) {
sawAlpha = true;
buffer.setHasAlpha(true);
}
RGBA32Buffer::setRGBA(*curr++, 0, 0, 0, 0);
}
}
}
}
}
// Update our status to be partially complete.
buffer.setStatus(RGBA32Buffer::FramePartial);
}
bool decode(const Vector<char>& data, RxIImageDecoder::RxIFormat fmt)
{
int i = 0;
int j = 0;
bool result = false;
RGBA32Buffer* frameBuffer = 0;
unsigned char* rgbData = 0;
if (!m_memoryManager)
return false;
m_memoryReader = new MemReader((unsigned char*)data.data(), data.size());
// The rest of the code expects that the first 8 bytes has already been read.
// The signature for these files is 8 bytes.
m_memoryReader->SetOffset(8);
switch (fmt) {
case RxIImageDecoder::FormatRdi:
m_rxi = RdiBirth(m_memoryManager, m_memoryReader);
break;
case RxIImageDecoder::FormatRgi:
m_rxi = RgiBirth(m_memoryManager, m_memoryReader);
break;
case RxIImageDecoder::FormatRpi:
m_rxi = RpiBirth(m_memoryManager, m_memoryReader);
break;
case RxIImageDecoder::FormatRwi:
m_rxi = RwiBirth(m_memoryManager, m_memoryReader);
break;
case RxIImageDecoder::FormatUnknown:
ASSERT_NOT_REACHED();
break;
}
if (!m_rxi) {
delete m_memoryReader;
m_memoryReader = 0;
return false;
}
m_format = fmt;
switch (fmt) {
case RxIImageDecoder::FormatRdi:
result = RdiGetWH(m_rxi, &m_w, &m_h);
break;
case RxIImageDecoder::FormatRgi:
result = RgiGetWH(m_rxi, &m_w, &m_h);
break;
case RxIImageDecoder::FormatRpi:
result = RpiGetWH(m_rxi, &m_w, &m_h);
break;
case RxIImageDecoder::FormatRwi:
result = RwiGetWH(m_rxi, &m_w, &m_h);
break;
case RxIImageDecoder::FormatUnknown:
ASSERT_NOT_REACHED();
break;
}
if (!result) {
delete m_memoryReader;
m_memoryReader = 0;
return false;
}
// We can fill in the size now that the header is available.
if (!m_decoder->setSize(m_w, m_h))
return m_decoder->setFailed();
frameBuffer = m_decoder->getUntouchedFrameBufferAtIndex(0);
if (!frameBuffer) {
delete m_memoryReader;
m_memoryReader = 0;
m_sizeInitialized = false;
return false;
}
if (frameBuffer->status() == RGBA32Buffer::FrameEmpty) {
if (!frameBuffer->setSize(m_w, m_h))
return m_decoder->setFailed();
frameBuffer->setStatus(RGBA32Buffer::FramePartial);
if ( fmt == RxIImageDecoder::FormatRpi ) {
// RPI format has alpha which we must support.
frameBuffer->setHasAlpha(true);
} else {
frameBuffer->setHasAlpha(false);
}
// the frame always fills the entire image.
frameBuffer->setRect(IntRect(IntPoint(0, 0), m_decoder->size()));
}
// note that we don't cleanup frameBuffer at all since we didn't allocate it.
if ( fmt == RxIImageDecoder::FormatRgi ) {
rgbData = (unsigned char*) malloc(m_w * m_h * 3);
} else if ( fmt == RxIImageDecoder::FormatRpi ) {
// extra channel is for alpha
rgbData = (unsigned char*) malloc(m_w * m_h * 4);
}
MemWriter mw(m_w * m_h * 3);
switch (fmt) {
case RxIImageDecoder::FormatRdi:
result = RdiGetRGB(m_rxi, &mw);
break;
case RxIImageDecoder::FormatRgi:
result = RgiGetRGB(m_rxi, rgbData);
break;
case RxIImageDecoder::FormatRpi:
result = RpiGetRGB(m_rxi, rgbData);
break;
case RxIImageDecoder::FormatRwi:
result = RwiGetRGB(m_rxi, &mw);
break;
case RxIImageDecoder::FormatUnknown:
ASSERT_NOT_REACHED();
break;
}
if (result) {
unsigned char* ptr = 0;
if ((fmt == RxIImageDecoder::FormatRdi) || (fmt == RxIImageDecoder::FormatRwi))
ptr = (unsigned char*)mw.GetBuffer();
else
ptr = rgbData;
for (i = 0; i < m_h; ++i) {
for (j = 0; j < m_w; ++j) {
unsigned char r, g, b;
unsigned char a = 0xFF;
r = *ptr;
ptr++;
g = *ptr;
ptr++;
b = *ptr;
ptr++;
if ( fmt == RxIImageDecoder::FormatRpi ) {
a = *ptr;
ptr++;
}
frameBuffer->setRGBA(j, i, r, g, b, a);
}
}
}
m_decoder->rxiComplete();
// cleaning up
free(rgbData);
rgbData = 0;
delete m_memoryReader;
m_memoryReader = 0;
m_sizeInitialized = false;
switch (fmt) {
case RxIImageDecoder::FormatRdi:
RdiDeath(m_rxi);
break;
case RxIImageDecoder::FormatRgi:
RgiDeath(m_rxi);
break;
case RxIImageDecoder::FormatRpi:
RpiDeath(m_rxi);
break;
case RxIImageDecoder::FormatRwi:
RwiDeath(m_rxi);
break;
case RxIImageDecoder::FormatUnknown:
ASSERT_NOT_REACHED();
break;
}
m_rxi = 0;
return true;
}