blob: 36efdd84ea9005cdf62bd8aaac31684359c1d02a [file] [log] [blame]
/*
* Copyright 2012 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/**
* Functions to transform scanlines between packed-pixel formats.
*/
#include "SkBitmap.h"
#include "SkColor.h"
#include "SkColorPriv.h"
#include "SkPreConfig.h"
#include "SkUnPreMultiply.h"
/**
* Function template for transforming scanlines.
* Transform 'width' pixels from 'src' buffer into 'dst' buffer,
* repacking color channel data as appropriate for the given transformation.
*/
typedef void (*transform_scanline_proc)(const char* SK_RESTRICT src,
int width, char* SK_RESTRICT dst);
/**
* Identity transformation: just copy bytes from src to dst.
*/
static void transform_scanline_memcpy(const char* SK_RESTRICT src, int width,
char* SK_RESTRICT dst) {
memcpy(dst, src, width);
}
/**
* Transform from kRGB_565_Config to 3-bytes-per-pixel RGB.
* Alpha channel data is not present in kRGB_565_Config format, so there is no
* alpha channel data to preserve.
*/
static void transform_scanline_565(const char* SK_RESTRICT src, int width,
char* SK_RESTRICT dst) {
const uint16_t* SK_RESTRICT srcP = (const uint16_t*)src;
for (int i = 0; i < width; i++) {
unsigned c = *srcP++;
*dst++ = SkPacked16ToR32(c);
*dst++ = SkPacked16ToG32(c);
*dst++ = SkPacked16ToB32(c);
}
}
/**
* Transform from kARGB_8888_Config to 3-bytes-per-pixel RGB.
* Alpha channel data, if any, is abandoned.
*/
static void transform_scanline_888(const char* SK_RESTRICT src, int width,
char* SK_RESTRICT dst) {
const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src;
for (int i = 0; i < width; i++) {
SkPMColor c = *srcP++;
*dst++ = SkGetPackedR32(c);
*dst++ = SkGetPackedG32(c);
*dst++ = SkGetPackedB32(c);
}
}
/**
* Transform from kARGB_4444_Config to 3-bytes-per-pixel RGB.
* Alpha channel data, if any, is abandoned.
*/
static void transform_scanline_444(const char* SK_RESTRICT src, int width,
char* SK_RESTRICT dst) {
const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src;
for (int i = 0; i < width; i++) {
SkPMColor16 c = *srcP++;
*dst++ = SkPacked4444ToR32(c);
*dst++ = SkPacked4444ToG32(c);
*dst++ = SkPacked4444ToB32(c);
}
}
/**
* Transform from kARGB_8888_Config to 4-bytes-per-pixel RGBA.
* (This would be the identity transformation, except for byte-order and
* scaling of RGB based on alpha channel).
*/
static void transform_scanline_8888(const char* SK_RESTRICT src, int width,
char* SK_RESTRICT dst) {
const SkPMColor* SK_RESTRICT srcP = (const SkPMColor*)src;
const SkUnPreMultiply::Scale* SK_RESTRICT table =
SkUnPreMultiply::GetScaleTable();
for (int i = 0; i < width; i++) {
SkPMColor c = *srcP++;
unsigned a = SkGetPackedA32(c);
unsigned r = SkGetPackedR32(c);
unsigned g = SkGetPackedG32(c);
unsigned b = SkGetPackedB32(c);
if (0 != a && 255 != a) {
SkUnPreMultiply::Scale scale = table[a];
r = SkUnPreMultiply::ApplyScale(scale, r);
g = SkUnPreMultiply::ApplyScale(scale, g);
b = SkUnPreMultiply::ApplyScale(scale, b);
}
*dst++ = r;
*dst++ = g;
*dst++ = b;
*dst++ = a;
}
}
/**
* Transform from kARGB_8888_Config to 4-bytes-per-pixel RGBA,
* with scaling of RGB based on alpha channel.
*/
static void transform_scanline_4444(const char* SK_RESTRICT src, int width,
char* SK_RESTRICT dst) {
const SkPMColor16* SK_RESTRICT srcP = (const SkPMColor16*)src;
const SkUnPreMultiply::Scale* SK_RESTRICT table =
SkUnPreMultiply::GetScaleTable();
for (int i = 0; i < width; i++) {
SkPMColor16 c = *srcP++;
unsigned a = SkPacked4444ToA32(c);
unsigned r = SkPacked4444ToR32(c);
unsigned g = SkPacked4444ToG32(c);
unsigned b = SkPacked4444ToB32(c);
if (0 != a && 255 != a) {
SkUnPreMultiply::Scale scale = table[a];
r = SkUnPreMultiply::ApplyScale(scale, r);
g = SkUnPreMultiply::ApplyScale(scale, g);
b = SkUnPreMultiply::ApplyScale(scale, b);
}
*dst++ = r;
*dst++ = g;
*dst++ = b;
*dst++ = a;
}
}