bool SkScaledCodec::onDimensionsSupported(const SkISize& dim) {
// Check with fCodec first. No need to call the non-virtual version, which
// just checks if it matches the original, since a match means this method
// will not be called.
if (fCodec->onDimensionsSupported(dim)) {
return true;
}
// FIXME: These variables are unused, but are needed by scaling_supported.
// This class could also cache these values, and avoid calling this in
// onGetPixels (since getPixels already calls it).
int sampleX;
int sampleY;
return scaling_supported(dim, this->getInfo().dimensions(), &sampleX, &sampleY);
}
SkCodec::Result SkScaledCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst,
size_t rowBytes, const Options& options,
SkPMColor ctable[], int* ctableCount) {
if (options.fSubset) {
// Subsets are not supported.
return kUnimplemented;
}
Result result = fScanlineDecoder->start(requestedInfo, &options, ctable, ctableCount);
if (kSuccess == result) {
// native decode supported
return fScanlineDecoder->getScanlines(dst, requestedInfo.height(), rowBytes);
}
if (kInvalidScale != result) {
// no scaling requested
return result;
}
// scaling requested
int sampleX;
int sampleY;
if (!scaling_supported(requestedInfo, fScanlineDecoder->getInfo(), &sampleX, &sampleY)) {
return kInvalidScale;
}
// set first sample pixel in y direction
int Y0 = sampleY >> 1;
int dstHeight = requestedInfo.height();
int srcHeight = fScanlineDecoder->getInfo().height();
SkImageInfo info = requestedInfo;
// use original height as scanlineDecoder does not support y sampling natively
info = info.makeWH(requestedInfo.width(), srcHeight);
// update scanlineDecoder with new info
result = fScanlineDecoder->start(info, &options, ctable, ctableCount);
if (kSuccess != result) {
return result;
}
const bool requiresPostYSampling = fScanlineDecoder->requiresPostYSampling();
if (requiresPostYSampling) {
SkAutoMalloc storage(srcHeight * rowBytes);
uint8_t* storagePtr = static_cast<uint8_t*>(storage.get());
result = fScanlineDecoder->getScanlines(storagePtr, srcHeight, rowBytes);
if (kSuccess != result) {
return result;
}
storagePtr += Y0 * rowBytes;
for (int y = 0; y < dstHeight; y++) {
memcpy(dst, storagePtr, rowBytes);
storagePtr += sampleY * rowBytes;
dst = SkTAddOffset<void>(dst, rowBytes);
}
} else {
// does not require post y sampling
result = fScanlineDecoder->skipScanlines(Y0);
if (kSuccess != result) {
return result;
}
for (int y = 0; y < dstHeight; y++) {
result = fScanlineDecoder->getScanlines(dst, 1, rowBytes);
if (kSuccess != result) {
return result;
}
if (y < dstHeight - 1) {
result = fScanlineDecoder->skipScanlines(sampleY - 1);
if (kSuccess != result) {
return result;
}
}
dst = SkTAddOffset<void>(dst, rowBytes);
}
}
return kSuccess;
}
SkCodec::Result SkScaledCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst,
size_t rowBytes, const Options& options,
SkPMColor ctable[], int* ctableCount,
int* rowsDecoded) {
if (options.fSubset) {
// Subsets are not supported.
return kUnimplemented;
}
if (fCodec->dimensionsSupported(requestedInfo.dimensions())) {
// Make sure that the parent class does not fill on an incomplete decode, since
// fCodec will take care of filling the uninitialized lines.
*rowsDecoded = requestedInfo.height();
return fCodec->getPixels(requestedInfo, dst, rowBytes, &options, ctable, ctableCount);
}
// scaling requested
int sampleX;
int sampleY;
if (!scaling_supported(requestedInfo.dimensions(), fCodec->getInfo().dimensions(),
&sampleX, &sampleY)) {
// onDimensionsSupported would have returned false, meaning we should never reach here.
SkASSERT(false);
return kInvalidScale;
}
// set first sample pixel in y direction
const int Y0 = get_start_coord(sampleY);
const int dstHeight = requestedInfo.height();
const int srcWidth = fCodec->getInfo().width();
const int srcHeight = fCodec->getInfo().height();
const SkImageInfo info = requestedInfo.makeWH(srcWidth, srcHeight);
Result result = fCodec->startScanlineDecode(info, &options, ctable, ctableCount);
if (kSuccess != result) {
return result;
}
SkSampler* sampler = fCodec->getSampler(true);
if (!sampler) {
return kUnimplemented;
}
if (sampler->setSampleX(sampleX) != requestedInfo.width()) {
return kInvalidScale;
}
switch(fCodec->getScanlineOrder()) {
case SkCodec::kTopDown_SkScanlineOrder: {
if (!fCodec->skipScanlines(Y0)) {
*rowsDecoded = 0;
return kIncompleteInput;
}
for (int y = 0; y < dstHeight; y++) {
if (1 != fCodec->getScanlines(dst, 1, rowBytes)) {
// The failed call to getScanlines() will take care of
// filling the failed row, so we indicate that we have
// decoded (y + 1) rows.
*rowsDecoded = y + 1;
return kIncompleteInput;
}
if (y < dstHeight - 1) {
if (!fCodec->skipScanlines(sampleY - 1)) {
*rowsDecoded = y + 1;
return kIncompleteInput;
}
}
dst = SkTAddOffset<void>(dst, rowBytes);
}
return kSuccess;
}
case SkCodec::kBottomUp_SkScanlineOrder:
case SkCodec::kOutOfOrder_SkScanlineOrder: {
Result result = kSuccess;
int y;
for (y = 0; y < srcHeight; y++) {
int srcY = fCodec->nextScanline();
if (is_coord_necessary(srcY, sampleY, dstHeight)) {
void* dstPtr = SkTAddOffset<void>(dst, rowBytes * get_dst_coord(srcY, sampleY));
if (1 != fCodec->getScanlines(dstPtr, 1, rowBytes)) {
result = kIncompleteInput;
break;
}
} else {
if (!fCodec->skipScanlines(1)) {
result = kIncompleteInput;
break;
}
}
}
// We handle filling uninitialized memory here instead of in the parent class.
// The parent class does not know that we are sampling.
if (kIncompleteInput == result) {
const uint32_t fillValue = fCodec->getFillValue(requestedInfo.colorType(),
requestedInfo.alphaType());
for (; y < srcHeight; y++) {
int srcY = fCodec->outputScanline(y);
if (is_coord_necessary(srcY, sampleY, dstHeight)) {
void* dstRow = SkTAddOffset<void>(dst,
rowBytes * get_dst_coord(srcY, sampleY));
SkSampler::Fill(requestedInfo.makeWH(requestedInfo.width(), 1), dstRow,
rowBytes, fillValue, options.fZeroInitialized);
}
}
*rowsDecoded = dstHeight;
}
return result;
}
case SkCodec::kNone_SkScanlineOrder: {
SkAutoMalloc storage(srcHeight * rowBytes);
uint8_t* storagePtr = static_cast<uint8_t*>(storage.get());
int scanlines = fCodec->getScanlines(storagePtr, srcHeight, rowBytes);
storagePtr += Y0 * rowBytes;
scanlines -= Y0;
int y = 0;
while (y < dstHeight && scanlines > 0) {
memcpy(dst, storagePtr, rowBytes);
storagePtr += sampleY * rowBytes;
dst = SkTAddOffset<void>(dst, rowBytes);
scanlines -= sampleY;
y++;
}
if (y < dstHeight) {
// fCodec has already handled filling uninitialized memory.
*rowsDecoded = dstHeight;
return kIncompleteInput;
}
return kSuccess;
}
default:
SkASSERT(false);
return kUnimplemented;
}
}
