Prepare sRGB encoding conversion for the removal of GrPixelConfig
Standardizes that GrGpu subclass's onRead/WritePixels never do sRGB<->linear conversion. This means that they can eventually take a color type rather than config. It also means direct callers of GrGpu::read/writePixels can never expect conversion (which in practice is no change).
Consolidate logic about whether to do sRGB<->linear encoding conversions in GrContext::read/writeSurfacePixels helpers. No change in when conversions are done (yet). This prepares this logic to operate on SkColorSpace and color type rather than config WRT the CPU data.
Bug: skia:6718
Change-Id: I346d669624861578f1bb9ea465a7ab4b549117fa
Reviewed-on: https://skia-review.googlesource.com/105286
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 09985e6..f8522f0 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -542,6 +542,63 @@
(kRGBA_8888_GrPixelConfig == config || kBGRA_8888_GrPixelConfig == config);
}
+static GrSRGBConversion determine_write_pixels_srgb_conversion(
+ GrPixelConfig srcConfig,
+ const SkColorSpace* srcColorSpace,
+ GrSRGBEncoded dstSRGBEncoded,
+ const SkColorSpace* dstColorSpace) {
+ // No support for sRGB-encoded alpha.
+ if (GrPixelConfigIsAlphaOnly(srcConfig)) {
+ return GrSRGBConversion::kNone;
+ }
+ // When the destination has no color space or it has a ~sRGB gamma but isn't sRGB encoded
+ // (because of caps) then we act in "legacy" mode where no conversions are performed.
+ if (!dstColorSpace ||
+ (dstColorSpace->gammaCloseToSRGB() && GrSRGBEncoded::kNo == dstSRGBEncoded)) {
+ return GrSRGBConversion::kNone;
+ }
+ // Similarly, if the src was sRGB gamma and 8888 but we didn't choose a sRGB config we must be
+ // in legacy mode. For now, anyway.
+ if (srcColorSpace && srcColorSpace->gammaCloseToSRGB() &&
+ GrSRGBEncoded::kNo == GrPixelConfigIsSRGBEncoded(srcConfig) &&
+ GrPixelConfigIs8888Unorm(srcConfig)) {
+ return GrSRGBConversion::kNone;
+ }
+
+ bool srcColorSpaceIsSRGB = srcColorSpace && srcColorSpace->gammaCloseToSRGB();
+ bool dstColorSpaceIsSRGB = dstColorSpace->gammaCloseToSRGB();
+
+ // For now we are assuming that if color space of the dst does not have sRGB gamma then the
+ // texture format is not sRGB encoded and vice versa. Note that we already checked for "legacy"
+ // mode being forced on by caps above. This may change in the future.
+ SkASSERT(dstColorSpaceIsSRGB == (GrSRGBEncoded::kYes == dstSRGBEncoded));
+
+ // Similarly we are assuming that if the color space of the src does not have sRGB gamma then
+ // the CPU pixels don't have a sRGB pixel config. This will become moot soon as we will not
+ // be using GrPixelConfig to describe CPU pixel allocations.
+ SkASSERT(srcColorSpaceIsSRGB == GrPixelConfigIsSRGB(srcConfig));
+
+ if (srcColorSpaceIsSRGB == dstColorSpaceIsSRGB) {
+ return GrSRGBConversion::kNone;
+ }
+ return srcColorSpaceIsSRGB ? GrSRGBConversion::kSRGBToLinear : GrSRGBConversion::kLinearToSRGB;
+}
+
+static GrSRGBConversion determine_read_pixels_srgb_conversion(
+ GrSRGBEncoded srcSRGBEncoded,
+ const SkColorSpace* srcColorSpace,
+ GrPixelConfig dstConfig,
+ const SkColorSpace* dstColorSpace) {
+ // This is symmetrical with the write version.
+ switch (determine_write_pixels_srgb_conversion(dstConfig, dstColorSpace, srcSRGBEncoded,
+ srcColorSpace)) {
+ case GrSRGBConversion::kNone: return GrSRGBConversion::kNone;
+ case GrSRGBConversion::kLinearToSRGB: return GrSRGBConversion::kSRGBToLinear;
+ case GrSRGBConversion::kSRGBToLinear: return GrSRGBConversion::kLinearToSRGB;
+ }
+ return GrSRGBConversion::kNone;
+}
+
bool GrContextPriv::writeSurfacePixels(GrSurfaceContext* dst,
int left, int top, int width, int height,
GrPixelConfig srcConfig, SkColorSpace* srcColorSpace,
@@ -590,8 +647,12 @@
GrGpu::DrawPreference drawPreference = premulOnGpu ? GrGpu::kCallerPrefersDraw_DrawPreference
: GrGpu::kNoDraw_DrawPreference;
GrGpu::WritePixelTempDrawInfo tempDrawInfo;
+ GrSRGBConversion srgbConversion = determine_write_pixels_srgb_conversion(
+ srcConfig, srcColorSpace, GrPixelConfigIsSRGBEncoded(dstProxy->config()),
+ dst->colorSpaceInfo().colorSpace());
if (!fContext->fGpu->getWritePixelsInfo(dstSurface, dstProxy->origin(), width, height,
- srcConfig, &drawPreference, &tempDrawInfo)) {
+ srcConfig, srgbConversion, &drawPreference,
+ &tempDrawInfo)) {
return false;
}
@@ -723,8 +784,12 @@
GrGpu::DrawPreference drawPreference = unpremulOnGpu ? GrGpu::kCallerPrefersDraw_DrawPreference
: GrGpu::kNoDraw_DrawPreference;
GrGpu::ReadPixelTempDrawInfo tempDrawInfo;
+ GrSRGBConversion srgbConversion = determine_read_pixels_srgb_conversion(
+ GrPixelConfigIsSRGBEncoded(srcProxy->config()), src->colorSpaceInfo().colorSpace(),
+ dstConfig, dstColorSpace);
if (!fContext->fGpu->getReadPixelsInfo(srcSurface, srcProxy->origin(), width, height, rowBytes,
- dstConfig, &drawPreference, &tempDrawInfo)) {
+ dstConfig, srgbConversion, &drawPreference,
+ &tempDrawInfo)) {
return false;
}