73a5d53d96
git-svn-id: http://skia.googlecode.com/svn/trunk@12283 2bbb7eff-a529-9590-31e7-b0007b416f81
124 lines
3.5 KiB
C
124 lines
3.5 KiB
C
/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkImageInfo_DEFINED
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#define SkImageInfo_DEFINED
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#include "SkTypes.h"
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/**
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* Describes how to interpret the alpha compoent of a pixel.
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*/
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enum SkAlphaType {
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/**
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* All pixels should be treated as opaque, regardless of the value stored
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* in their alpha field. Used for legacy images that wrote 0 or garbarge
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* in their alpha field, but intended the RGB to be treated as opaque.
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*/
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kIgnore_SkAlphaType,
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/**
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* All pixels are stored as opaque. This differs slightly from kIgnore in
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* that kOpaque has correct "opaque" values stored in the pixels, while
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* kIgnore may not, but in both cases the caller should treat the pixels
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* as opaque.
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*/
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kOpaque_SkAlphaType,
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/**
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* All pixels have their alpha premultiplied in their color components.
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* This is the natural format for the rendering target pixels.
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*/
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kPremul_SkAlphaType,
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/**
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* All pixels have their color components stored without any regard to the
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* alpha. e.g. this is the default configuration for PNG images.
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*
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* This alpha-type is ONLY supported for input images. Rendering cannot
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* generate this on output.
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*/
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kUnpremul_SkAlphaType,
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kLastEnum_SkAlphaType = kUnpremul_SkAlphaType
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};
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static inline bool SkAlphaTypeIsOpaque(SkAlphaType at) {
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SK_COMPILE_ASSERT(kIgnore_SkAlphaType < kOpaque_SkAlphaType, bad_alphatype_order);
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SK_COMPILE_ASSERT(kPremul_SkAlphaType > kOpaque_SkAlphaType, bad_alphatype_order);
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SK_COMPILE_ASSERT(kUnpremul_SkAlphaType > kOpaque_SkAlphaType, bad_alphatype_order);
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return (unsigned)at <= kOpaque_SkAlphaType;
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}
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///////////////////////////////////////////////////////////////////////////////
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/**
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* Describes how to interpret the components of a pixel.
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*/
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enum SkColorType {
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kAlpha_8_SkColorType,
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kRGB_565_SkColorType,
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kRGBA_8888_SkColorType,
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kBGRA_8888_SkColorType,
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kIndex8_SkColorType,
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kLastEnum_SkColorType = kIndex8_SkColorType,
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#if SK_PMCOLOR_BYTE_ORDER(B,G,R,A)
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kPMColor_SkColorType = kBGRA_8888_SkColorType
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#elif SK_PMCOLOR_BYTE_ORDER(R,G,B,A)
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kPMColor_SkColorType = kRGBA_8888_SkColorType
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#else
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#error "SK_*32_SHFIT values must correspond to BGRA or RGBA byte order"
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#endif
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};
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static int SkColorTypeBytesPerPixel(SkColorType ct) {
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static const uint8_t gSize[] = {
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1, // Alpha_8
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2, // RGB_565
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4, // RGBA_8888
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4, // BGRA_8888
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1, // kIndex_8
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};
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SK_COMPILE_ASSERT(SK_ARRAY_COUNT(gSize) == (size_t)(kLastEnum_SkColorType + 1),
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size_mismatch_with_SkColorType_enum);
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SkASSERT((size_t)ct < SK_ARRAY_COUNT(gSize));
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return gSize[ct];
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}
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///////////////////////////////////////////////////////////////////////////////
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/**
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* Describe an image's dimensions and pixel type.
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*/
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struct SkImageInfo {
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int fWidth;
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int fHeight;
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SkColorType fColorType;
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SkAlphaType fAlphaType;
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bool isOpaque() const {
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return SkAlphaTypeIsOpaque(fAlphaType);
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}
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int bytesPerPixel() const {
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return SkColorTypeBytesPerPixel(fColorType);
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}
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bool operator==(const SkImageInfo& other) const {
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return 0 == memcmp(this, &other, sizeof(other));
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}
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bool operator!=(const SkImageInfo& other) const {
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return 0 != memcmp(this, &other, sizeof(other));
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}
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};
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#endif
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