gecko-dev/gfx/layers/LayerUtils.cpp
Tor Arvid Lund a9c37a9053 Bug 948765 - Add a LayerUtils file in gfx/layers. r=nical
This file is currently just a helper for doing PremultiplySurface in
Moz2D. It corresponds to an existing Thebes one in the gfxUtils class.

An upcoming patch will require this PremultiplySurface method. The
existing one in gfxUtils has been renamed internally to
DeprecatedPremultiplyTables.
2014-02-12 10:07:46 -05:00

80 lines
2.2 KiB
C++

/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "LayerUtils.h"
#include "PremultiplyTables.h"
namespace mozilla {
namespace layers {
using namespace mozilla::gfx;
static inline const uint8_t PremultiplyValue(uint8_t a, uint8_t v) {
return PremultiplyTable[a*256+v];
}
static inline const uint8_t UnpremultiplyValue(uint8_t a, uint8_t v) {
return UnpremultiplyTable[a*256+v];
}
void
PremultiplySurface(DataSourceSurface* srcSurface,
DataSourceSurface* destSurface)
{
if (!destSurface)
destSurface = srcSurface;
IntSize srcSize = srcSurface->GetSize();
MOZ_ASSERT(srcSurface->GetFormat() == destSurface->GetFormat() &&
srcSize.width == destSurface->GetSize().width &&
srcSize.height == destSurface->GetSize().height &&
srcSurface->Stride() == destSurface->Stride(),
"Source and destination surfaces don't have identical characteristics");
MOZ_ASSERT(srcSurface->Stride() == srcSize.width * 4,
"Source surface stride isn't tightly packed");
// Only premultiply ARGB32
if (srcSurface->GetFormat() != SurfaceFormat::B8G8R8A8) {
if (destSurface != srcSurface) {
memcpy(destSurface->GetData(), srcSurface->GetData(),
srcSurface->Stride() * srcSize.height);
}
return;
}
uint8_t *src = srcSurface->GetData();
uint8_t *dst = destSurface->GetData();
uint32_t dim = srcSize.width * srcSize.height;
for (uint32_t i = 0; i < dim; ++i) {
#ifdef IS_LITTLE_ENDIAN
uint8_t b = *src++;
uint8_t g = *src++;
uint8_t r = *src++;
uint8_t a = *src++;
*dst++ = PremultiplyValue(a, b);
*dst++ = PremultiplyValue(a, g);
*dst++ = PremultiplyValue(a, r);
*dst++ = a;
#else
uint8_t a = *src++;
uint8_t r = *src++;
uint8_t g = *src++;
uint8_t b = *src++;
*dst++ = a;
*dst++ = PremultiplyValue(a, r);
*dst++ = PremultiplyValue(a, g);
*dst++ = PremultiplyValue(a, b);
#endif
}
}
}
}