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