133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// Copyright 2014 Google Inc. All Rights Reserved. 233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// 333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// Use of this source code is governed by a BSD-style license 433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// that can be found in the COPYING file in the root of the source 533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// tree. An additional intellectual property rights grant can be found 633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// in the file PATENTS. All contributing project authors may 733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// be found in the AUTHORS file in the root of the source tree. 833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// ----------------------------------------------------------------------------- 933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// 1033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// WebPPicture tools: alpha handling, etc. 1133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// 1233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// Author: Skal (pascal.massimino@gmail.com) 1333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 1433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#include "./vp8enci.h" 1533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#include "../dsp/yuv.h" 1633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 1733f74dabbc7920a65ed435d7417987589febdc16Vikas Arorastatic WEBP_INLINE uint32_t MakeARGB32(int r, int g, int b) { 1833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora return (0xff000000u | (r << 16) | (g << 8) | b); 1933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora} 2033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 2133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora//------------------------------------------------------------------------------ 2233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// Helper: clean up fully transparent area to help compressibility. 2333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 2433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#define SIZE 8 2533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#define SIZE2 (SIZE / 2) 2633f74dabbc7920a65ed435d7417987589febdc16Vikas Arorastatic int is_transparent_area(const uint8_t* ptr, int stride, int size) { 2733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int y, x; 2833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < size; ++y) { 2933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < size; ++x) { 3033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (ptr[x]) { 3133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora return 0; 3233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 3333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 3433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora ptr += stride; 3533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 3633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora return 1; 3733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora} 3833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 3933f74dabbc7920a65ed435d7417987589febdc16Vikas Arorastatic int is_transparent_argb_area(const uint32_t* ptr, int stride, int size) { 4033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int y, x; 4133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < size; ++y) { 4233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < size; ++x) { 4333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (ptr[x] & 0xff000000u) { 4433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora return 0; 4533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 4633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 4733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora ptr += stride; 4833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 4933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora return 1; 5033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora} 5133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 5233f74dabbc7920a65ed435d7417987589febdc16Vikas Arorastatic void flatten(uint8_t* ptr, int v, int stride, int size) { 5333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int y; 5433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < size; ++y) { 5533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora memset(ptr, v, size); 5633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora ptr += stride; 5733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 5833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora} 5933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 6033f74dabbc7920a65ed435d7417987589febdc16Vikas Arorastatic void flatten_argb(uint32_t* ptr, uint32_t v, int stride, int size) { 6133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int x, y; 6233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < size; ++y) { 6333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < size; ++x) ptr[x] = v; 6433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora ptr += stride; 6533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 6633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora} 6733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 6833f74dabbc7920a65ed435d7417987589febdc16Vikas Aroravoid WebPCleanupTransparentArea(WebPPicture* pic) { 6933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int x, y, w, h; 7033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (pic == NULL) return; 7133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora w = pic->width / SIZE; 7233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora h = pic->height / SIZE; 7333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 7433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora // note: we ignore the left-overs on right/bottom 7533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (pic->use_argb) { 7633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora uint32_t argb_value = 0; 7733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < h; ++y) { 7833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int need_reset = 1; 7933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < w; ++x) { 8033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int off = (y * pic->argb_stride + x) * SIZE; 8133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (is_transparent_argb_area(pic->argb + off, pic->argb_stride, SIZE)) { 8233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (need_reset) { 8333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora argb_value = pic->argb[off]; 8433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora need_reset = 0; 8533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 8633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora flatten_argb(pic->argb + off, argb_value, pic->argb_stride, SIZE); 8733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } else { 8833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora need_reset = 1; 8933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 9033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 9133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 9233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } else { 9333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const uint8_t* const a_ptr = pic->a; 9433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int values[3] = { 0 }; 9533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (a_ptr == NULL) return; // nothing to do 9633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < h; ++y) { 9733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int need_reset = 1; 9833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < w; ++x) { 9933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int off_a = (y * pic->a_stride + x) * SIZE; 10033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int off_y = (y * pic->y_stride + x) * SIZE; 10133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int off_uv = (y * pic->uv_stride + x) * SIZE2; 10233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (is_transparent_area(a_ptr + off_a, pic->a_stride, SIZE)) { 10333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (need_reset) { 10433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora values[0] = pic->y[off_y]; 10533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora values[1] = pic->u[off_uv]; 10633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora values[2] = pic->v[off_uv]; 10733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora need_reset = 0; 10833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 10933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora flatten(pic->y + off_y, values[0], pic->y_stride, SIZE); 11033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora flatten(pic->u + off_uv, values[1], pic->uv_stride, SIZE2); 11133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora flatten(pic->v + off_uv, values[2], pic->uv_stride, SIZE2); 11233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } else { 11333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora need_reset = 1; 11433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 11533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 11633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 11733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 11833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora} 11933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 12033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#undef SIZE 12133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#undef SIZE2 12233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 12333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora//------------------------------------------------------------------------------ 12433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora// Blend color and remove transparency info 12533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 12633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#define BLEND(V0, V1, ALPHA) \ 12733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora ((((V0) * (255 - (ALPHA)) + (V1) * (ALPHA)) * 0x101) >> 16) 12833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#define BLEND_10BIT(V0, V1, ALPHA) \ 12933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora ((((V0) * (1020 - (ALPHA)) + (V1) * (ALPHA)) * 0x101) >> 18) 13033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 13133f74dabbc7920a65ed435d7417987589febdc16Vikas Aroravoid WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb) { 13233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int red = (background_rgb >> 16) & 0xff; 13333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int green = (background_rgb >> 8) & 0xff; 13433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int blue = (background_rgb >> 0) & 0xff; 13533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int x, y; 13633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (pic == NULL) return; 13733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (!pic->use_argb) { 13833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int uv_width = (pic->width >> 1); // omit last pixel during u/v loop 13933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int Y0 = VP8RGBToY(red, green, blue, YUV_HALF); 14033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora // VP8RGBToU/V expects the u/v values summed over four pixels 14133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int U0 = VP8RGBToU(4 * red, 4 * green, 4 * blue, 4 * YUV_HALF); 14233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int V0 = VP8RGBToV(4 * red, 4 * green, 4 * blue, 4 * YUV_HALF); 14333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int has_alpha = pic->colorspace & WEBP_CSP_ALPHA_BIT; 14433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (!has_alpha || pic->a == NULL) return; // nothing to do 14533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < pic->height; ++y) { 14633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora // Luma blending 14733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora uint8_t* const y_ptr = pic->y + y * pic->y_stride; 14833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora uint8_t* const a_ptr = pic->a + y * pic->a_stride; 14933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < pic->width; ++x) { 15033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int alpha = a_ptr[x]; 15133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (alpha < 0xff) { 15233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora y_ptr[x] = BLEND(Y0, y_ptr[x], a_ptr[x]); 15333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 15433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 15533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora // Chroma blending every even line 15633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if ((y & 1) == 0) { 15733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora uint8_t* const u = pic->u + (y >> 1) * pic->uv_stride; 15833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora uint8_t* const v = pic->v + (y >> 1) * pic->uv_stride; 15933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora uint8_t* const a_ptr2 = 16033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora (y + 1 == pic->height) ? a_ptr : a_ptr + pic->a_stride; 16133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < uv_width; ++x) { 16233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora // Average four alpha values into a single blending weight. 16333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora // TODO(skal): might lead to visible contouring. Can we do better? 16433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int alpha = 16533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora a_ptr[2 * x + 0] + a_ptr[2 * x + 1] + 16633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora a_ptr2[2 * x + 0] + a_ptr2[2 * x + 1]; 16733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora u[x] = BLEND_10BIT(U0, u[x], alpha); 16833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora v[x] = BLEND_10BIT(V0, v[x], alpha); 16933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 17033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (pic->width & 1) { // rightmost pixel 17133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int alpha = 2 * (a_ptr[2 * x + 0] + a_ptr2[2 * x + 0]); 17233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora u[x] = BLEND_10BIT(U0, u[x], alpha); 17333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora v[x] = BLEND_10BIT(V0, v[x], alpha); 17433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 17533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 17633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora memset(a_ptr, 0xff, pic->width); 17733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 17833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } else { 17933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora uint32_t* argb = pic->argb; 18033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const uint32_t background = MakeARGB32(red, green, blue); 18133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (y = 0; y < pic->height; ++y) { 18233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora for (x = 0; x < pic->width; ++x) { 18333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora const int alpha = (argb[x] >> 24) & 0xff; 18433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (alpha != 0xff) { 18533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora if (alpha > 0) { 18633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int r = (argb[x] >> 16) & 0xff; 18733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int g = (argb[x] >> 8) & 0xff; 18833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora int b = (argb[x] >> 0) & 0xff; 18933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora r = BLEND(red, r, alpha); 19033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora g = BLEND(green, g, alpha); 19133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora b = BLEND(blue, b, alpha); 19233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora argb[x] = MakeARGB32(r, g, b); 19333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } else { 19433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora argb[x] = background; 19533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 19633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 19733f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 19833f74dabbc7920a65ed435d7417987589febdc16Vikas Arora argb += pic->argb_stride; 19933f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 20033f74dabbc7920a65ed435d7417987589febdc16Vikas Arora } 20133f74dabbc7920a65ed435d7417987589febdc16Vikas Arora} 20233f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 20333f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#undef BLEND 20433f74dabbc7920a65ed435d7417987589febdc16Vikas Arora#undef BLEND_10BIT 20533f74dabbc7920a65ed435d7417987589febdc16Vikas Arora 20633f74dabbc7920a65ed435d7417987589febdc16Vikas Arora//------------------------------------------------------------------------------ 207