1 // Copyright 2014 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // WebPPicture tools: copy, crop, rescaling and view. 11 // 12 // Author: Skal (pascal.massimino (at) gmail.com) 13 14 #include <assert.h> 15 #include <stdlib.h> 16 17 #include "./vp8i_enc.h" 18 #include "../utils/rescaler_utils.h" 19 #include "../utils/utils.h" 20 21 #define HALVE(x) (((x) + 1) >> 1) 22 23 // Grab the 'specs' (writer, *opaque, width, height...) from 'src' and copy them 24 // into 'dst'. Mark 'dst' as not owning any memory. 25 static void PictureGrabSpecs(const WebPPicture* const src, 26 WebPPicture* const dst) { 27 assert(src != NULL && dst != NULL); 28 *dst = *src; 29 WebPPictureResetBuffers(dst); 30 } 31 32 //------------------------------------------------------------------------------ 33 34 // Adjust top-left corner to chroma sample position. 35 static void SnapTopLeftPosition(const WebPPicture* const pic, 36 int* const left, int* const top) { 37 if (!pic->use_argb) { 38 *left &= ~1; 39 *top &= ~1; 40 } 41 } 42 43 // Adjust top-left corner and verify that the sub-rectangle is valid. 44 static int AdjustAndCheckRectangle(const WebPPicture* const pic, 45 int* const left, int* const top, 46 int width, int height) { 47 SnapTopLeftPosition(pic, left, top); 48 if ((*left) < 0 || (*top) < 0) return 0; 49 if (width <= 0 || height <= 0) return 0; 50 if ((*left) + width > pic->width) return 0; 51 if ((*top) + height > pic->height) return 0; 52 return 1; 53 } 54 55 int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst) { 56 if (src == NULL || dst == NULL) return 0; 57 if (src == dst) return 1; 58 59 PictureGrabSpecs(src, dst); 60 if (!WebPPictureAlloc(dst)) return 0; 61 62 if (!src->use_argb) { 63 WebPCopyPlane(src->y, src->y_stride, 64 dst->y, dst->y_stride, dst->width, dst->height); 65 WebPCopyPlane(src->u, src->uv_stride, dst->u, dst->uv_stride, 66 HALVE(dst->width), HALVE(dst->height)); 67 WebPCopyPlane(src->v, src->uv_stride, dst->v, dst->uv_stride, 68 HALVE(dst->width), HALVE(dst->height)); 69 if (dst->a != NULL) { 70 WebPCopyPlane(src->a, src->a_stride, 71 dst->a, dst->a_stride, dst->width, dst->height); 72 } 73 } else { 74 WebPCopyPlane((const uint8_t*)src->argb, 4 * src->argb_stride, 75 (uint8_t*)dst->argb, 4 * dst->argb_stride, 76 4 * dst->width, dst->height); 77 } 78 return 1; 79 } 80 81 int WebPPictureIsView(const WebPPicture* picture) { 82 if (picture == NULL) return 0; 83 if (picture->use_argb) { 84 return (picture->memory_argb_ == NULL); 85 } 86 return (picture->memory_ == NULL); 87 } 88 89 int WebPPictureView(const WebPPicture* src, 90 int left, int top, int width, int height, 91 WebPPicture* dst) { 92 if (src == NULL || dst == NULL) return 0; 93 94 // verify rectangle position. 95 if (!AdjustAndCheckRectangle(src, &left, &top, width, height)) return 0; 96 97 if (src != dst) { // beware of aliasing! We don't want to leak 'memory_'. 98 PictureGrabSpecs(src, dst); 99 } 100 dst->width = width; 101 dst->height = height; 102 if (!src->use_argb) { 103 dst->y = src->y + top * src->y_stride + left; 104 dst->u = src->u + (top >> 1) * src->uv_stride + (left >> 1); 105 dst->v = src->v + (top >> 1) * src->uv_stride + (left >> 1); 106 dst->y_stride = src->y_stride; 107 dst->uv_stride = src->uv_stride; 108 if (src->a != NULL) { 109 dst->a = src->a + top * src->a_stride + left; 110 dst->a_stride = src->a_stride; 111 } 112 } else { 113 dst->argb = src->argb + top * src->argb_stride + left; 114 dst->argb_stride = src->argb_stride; 115 } 116 return 1; 117 } 118 119 //------------------------------------------------------------------------------ 120 // Picture cropping 121 122 int WebPPictureCrop(WebPPicture* pic, 123 int left, int top, int width, int height) { 124 WebPPicture tmp; 125 126 if (pic == NULL) return 0; 127 if (!AdjustAndCheckRectangle(pic, &left, &top, width, height)) return 0; 128 129 PictureGrabSpecs(pic, &tmp); 130 tmp.width = width; 131 tmp.height = height; 132 if (!WebPPictureAlloc(&tmp)) return 0; 133 134 if (!pic->use_argb) { 135 const int y_offset = top * pic->y_stride + left; 136 const int uv_offset = (top / 2) * pic->uv_stride + left / 2; 137 WebPCopyPlane(pic->y + y_offset, pic->y_stride, 138 tmp.y, tmp.y_stride, width, height); 139 WebPCopyPlane(pic->u + uv_offset, pic->uv_stride, 140 tmp.u, tmp.uv_stride, HALVE(width), HALVE(height)); 141 WebPCopyPlane(pic->v + uv_offset, pic->uv_stride, 142 tmp.v, tmp.uv_stride, HALVE(width), HALVE(height)); 143 144 if (tmp.a != NULL) { 145 const int a_offset = top * pic->a_stride + left; 146 WebPCopyPlane(pic->a + a_offset, pic->a_stride, 147 tmp.a, tmp.a_stride, width, height); 148 } 149 } else { 150 const uint8_t* const src = 151 (const uint8_t*)(pic->argb + top * pic->argb_stride + left); 152 WebPCopyPlane(src, pic->argb_stride * 4, (uint8_t*)tmp.argb, 153 tmp.argb_stride * 4, width * 4, height); 154 } 155 WebPPictureFree(pic); 156 *pic = tmp; 157 return 1; 158 } 159 160 //------------------------------------------------------------------------------ 161 // Simple picture rescaler 162 163 static void RescalePlane(const uint8_t* src, 164 int src_width, int src_height, int src_stride, 165 uint8_t* dst, 166 int dst_width, int dst_height, int dst_stride, 167 rescaler_t* const work, 168 int num_channels) { 169 WebPRescaler rescaler; 170 int y = 0; 171 WebPRescalerInit(&rescaler, src_width, src_height, 172 dst, dst_width, dst_height, dst_stride, 173 num_channels, work); 174 while (y < src_height) { 175 y += WebPRescalerImport(&rescaler, src_height - y, 176 src + y * src_stride, src_stride); 177 WebPRescalerExport(&rescaler); 178 } 179 } 180 181 static void AlphaMultiplyARGB(WebPPicture* const pic, int inverse) { 182 assert(pic->argb != NULL); 183 WebPMultARGBRows((uint8_t*)pic->argb, pic->argb_stride * sizeof(*pic->argb), 184 pic->width, pic->height, inverse); 185 } 186 187 static void AlphaMultiplyY(WebPPicture* const pic, int inverse) { 188 if (pic->a != NULL) { 189 WebPMultRows(pic->y, pic->y_stride, pic->a, pic->a_stride, 190 pic->width, pic->height, inverse); 191 } 192 } 193 194 int WebPPictureRescale(WebPPicture* pic, int width, int height) { 195 WebPPicture tmp; 196 int prev_width, prev_height; 197 rescaler_t* work; 198 199 if (pic == NULL) return 0; 200 prev_width = pic->width; 201 prev_height = pic->height; 202 if (!WebPRescalerGetScaledDimensions( 203 prev_width, prev_height, &width, &height)) { 204 return 0; 205 } 206 207 PictureGrabSpecs(pic, &tmp); 208 tmp.width = width; 209 tmp.height = height; 210 if (!WebPPictureAlloc(&tmp)) return 0; 211 212 if (!pic->use_argb) { 213 work = (rescaler_t*)WebPSafeMalloc(2ULL * width, sizeof(*work)); 214 if (work == NULL) { 215 WebPPictureFree(&tmp); 216 return 0; 217 } 218 // If present, we need to rescale alpha first (for AlphaMultiplyY). 219 if (pic->a != NULL) { 220 WebPInitAlphaProcessing(); 221 RescalePlane(pic->a, prev_width, prev_height, pic->a_stride, 222 tmp.a, width, height, tmp.a_stride, work, 1); 223 } 224 225 // We take transparency into account on the luma plane only. That's not 226 // totally exact blending, but still is a good approximation. 227 AlphaMultiplyY(pic, 0); 228 RescalePlane(pic->y, prev_width, prev_height, pic->y_stride, 229 tmp.y, width, height, tmp.y_stride, work, 1); 230 AlphaMultiplyY(&tmp, 1); 231 232 RescalePlane(pic->u, 233 HALVE(prev_width), HALVE(prev_height), pic->uv_stride, 234 tmp.u, 235 HALVE(width), HALVE(height), tmp.uv_stride, work, 1); 236 RescalePlane(pic->v, 237 HALVE(prev_width), HALVE(prev_height), pic->uv_stride, 238 tmp.v, 239 HALVE(width), HALVE(height), tmp.uv_stride, work, 1); 240 } else { 241 work = (rescaler_t*)WebPSafeMalloc(2ULL * width * 4, sizeof(*work)); 242 if (work == NULL) { 243 WebPPictureFree(&tmp); 244 return 0; 245 } 246 // In order to correctly interpolate colors, we need to apply the alpha 247 // weighting first (black-matting), scale the RGB values, and remove 248 // the premultiplication afterward (while preserving the alpha channel). 249 WebPInitAlphaProcessing(); 250 AlphaMultiplyARGB(pic, 0); 251 RescalePlane((const uint8_t*)pic->argb, prev_width, prev_height, 252 pic->argb_stride * 4, 253 (uint8_t*)tmp.argb, width, height, 254 tmp.argb_stride * 4, 255 work, 4); 256 AlphaMultiplyARGB(&tmp, 1); 257 } 258 WebPPictureFree(pic); 259 WebPSafeFree(work); 260 *pic = tmp; 261 return 1; 262 } 263 264 //------------------------------------------------------------------------------ 265
