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@gmail.com)
13
14 #include "src/webp/encode.h"
15
16 #include <assert.h>
17 #include <stdlib.h>
18
19 #include "src/enc/vp8i_enc.h"
20
21 #if !defined(WEBP_REDUCE_SIZE)
22 #include "src/utils/rescaler_utils.h"
23 #include "src/utils/utils.h"
24 #endif // !defined(WEBP_REDUCE_SIZE)
25
26 #define HALVE(x) (((x) + 1) >> 1)
27
28 // Grab the 'specs' (writer, *opaque, width, height...) from 'src' and copy them
29 // into 'dst'. Mark 'dst' as not owning any memory.
PictureGrabSpecs(const WebPPicture * const src,WebPPicture * const dst)30 static void PictureGrabSpecs(const WebPPicture* const src,
31 WebPPicture* const dst) {
32 assert(src != NULL && dst != NULL);
33 *dst = *src;
34 WebPPictureResetBuffers(dst);
35 }
36
37 //------------------------------------------------------------------------------
38
39 // Adjust top-left corner to chroma sample position.
SnapTopLeftPosition(const WebPPicture * const pic,int * const left,int * const top)40 static void SnapTopLeftPosition(const WebPPicture* const pic,
41 int* const left, int* const top) {
42 if (!pic->use_argb) {
43 *left &= ~1;
44 *top &= ~1;
45 }
46 }
47
48 // Adjust top-left corner and verify that the sub-rectangle is valid.
AdjustAndCheckRectangle(const WebPPicture * const pic,int * const left,int * const top,int width,int height)49 static int AdjustAndCheckRectangle(const WebPPicture* const pic,
50 int* const left, int* const top,
51 int width, int height) {
52 SnapTopLeftPosition(pic, left, top);
53 if ((*left) < 0 || (*top) < 0) return 0;
54 if (width <= 0 || height <= 0) return 0;
55 if ((*left) + width > pic->width) return 0;
56 if ((*top) + height > pic->height) return 0;
57 return 1;
58 }
59
60 #if !defined(WEBP_REDUCE_SIZE)
WebPPictureCopy(const WebPPicture * src,WebPPicture * dst)61 int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst) {
62 if (src == NULL || dst == NULL) return 0;
63 if (src == dst) return 1;
64
65 PictureGrabSpecs(src, dst);
66 if (!WebPPictureAlloc(dst)) return 0;
67
68 if (!src->use_argb) {
69 WebPCopyPlane(src->y, src->y_stride,
70 dst->y, dst->y_stride, dst->width, dst->height);
71 WebPCopyPlane(src->u, src->uv_stride, dst->u, dst->uv_stride,
72 HALVE(dst->width), HALVE(dst->height));
73 WebPCopyPlane(src->v, src->uv_stride, dst->v, dst->uv_stride,
74 HALVE(dst->width), HALVE(dst->height));
75 if (dst->a != NULL) {
76 WebPCopyPlane(src->a, src->a_stride,
77 dst->a, dst->a_stride, dst->width, dst->height);
78 }
79 } else {
80 WebPCopyPlane((const uint8_t*)src->argb, 4 * src->argb_stride,
81 (uint8_t*)dst->argb, 4 * dst->argb_stride,
82 4 * dst->width, dst->height);
83 }
84 return 1;
85 }
86 #endif // !defined(WEBP_REDUCE_SIZE)
87
WebPPictureIsView(const WebPPicture * picture)88 int WebPPictureIsView(const WebPPicture* picture) {
89 if (picture == NULL) return 0;
90 if (picture->use_argb) {
91 return (picture->memory_argb_ == NULL);
92 }
93 return (picture->memory_ == NULL);
94 }
95
WebPPictureView(const WebPPicture * src,int left,int top,int width,int height,WebPPicture * dst)96 int WebPPictureView(const WebPPicture* src,
97 int left, int top, int width, int height,
98 WebPPicture* dst) {
99 if (src == NULL || dst == NULL) return 0;
100
101 // verify rectangle position.
102 if (!AdjustAndCheckRectangle(src, &left, &top, width, height)) return 0;
103
104 if (src != dst) { // beware of aliasing! We don't want to leak 'memory_'.
105 PictureGrabSpecs(src, dst);
106 }
107 dst->width = width;
108 dst->height = height;
109 if (!src->use_argb) {
110 dst->y = src->y + top * src->y_stride + left;
111 dst->u = src->u + (top >> 1) * src->uv_stride + (left >> 1);
112 dst->v = src->v + (top >> 1) * src->uv_stride + (left >> 1);
113 dst->y_stride = src->y_stride;
114 dst->uv_stride = src->uv_stride;
115 if (src->a != NULL) {
116 dst->a = src->a + top * src->a_stride + left;
117 dst->a_stride = src->a_stride;
118 }
119 } else {
120 dst->argb = src->argb + top * src->argb_stride + left;
121 dst->argb_stride = src->argb_stride;
122 }
123 return 1;
124 }
125
126 #if !defined(WEBP_REDUCE_SIZE)
127 //------------------------------------------------------------------------------
128 // Picture cropping
129
WebPPictureCrop(WebPPicture * pic,int left,int top,int width,int height)130 int WebPPictureCrop(WebPPicture* pic,
131 int left, int top, int width, int height) {
132 WebPPicture tmp;
133
134 if (pic == NULL) return 0;
135 if (!AdjustAndCheckRectangle(pic, &left, &top, width, height)) return 0;
136
137 PictureGrabSpecs(pic, &tmp);
138 tmp.width = width;
139 tmp.height = height;
140 if (!WebPPictureAlloc(&tmp)) return 0;
141
142 if (!pic->use_argb) {
143 const int y_offset = top * pic->y_stride + left;
144 const int uv_offset = (top / 2) * pic->uv_stride + left / 2;
145 WebPCopyPlane(pic->y + y_offset, pic->y_stride,
146 tmp.y, tmp.y_stride, width, height);
147 WebPCopyPlane(pic->u + uv_offset, pic->uv_stride,
148 tmp.u, tmp.uv_stride, HALVE(width), HALVE(height));
149 WebPCopyPlane(pic->v + uv_offset, pic->uv_stride,
150 tmp.v, tmp.uv_stride, HALVE(width), HALVE(height));
151
152 if (tmp.a != NULL) {
153 const int a_offset = top * pic->a_stride + left;
154 WebPCopyPlane(pic->a + a_offset, pic->a_stride,
155 tmp.a, tmp.a_stride, width, height);
156 }
157 } else {
158 const uint8_t* const src =
159 (const uint8_t*)(pic->argb + top * pic->argb_stride + left);
160 WebPCopyPlane(src, pic->argb_stride * 4, (uint8_t*)tmp.argb,
161 tmp.argb_stride * 4, width * 4, height);
162 }
163 WebPPictureFree(pic);
164 *pic = tmp;
165 return 1;
166 }
167
168 //------------------------------------------------------------------------------
169 // Simple picture rescaler
170
RescalePlane(const uint8_t * src,int src_width,int src_height,int src_stride,uint8_t * dst,int dst_width,int dst_height,int dst_stride,rescaler_t * const work,int num_channels)171 static int RescalePlane(const uint8_t* src,
172 int src_width, int src_height, int src_stride,
173 uint8_t* dst,
174 int dst_width, int dst_height, int dst_stride,
175 rescaler_t* const work,
176 int num_channels) {
177 WebPRescaler rescaler;
178 int y = 0;
179 if (!WebPRescalerInit(&rescaler, src_width, src_height,
180 dst, dst_width, dst_height, dst_stride,
181 num_channels, work)) {
182 return 0;
183 }
184 while (y < src_height) {
185 y += WebPRescalerImport(&rescaler, src_height - y,
186 src + y * src_stride, src_stride);
187 WebPRescalerExport(&rescaler);
188 }
189 return 1;
190 }
191
AlphaMultiplyARGB(WebPPicture * const pic,int inverse)192 static void AlphaMultiplyARGB(WebPPicture* const pic, int inverse) {
193 assert(pic->argb != NULL);
194 WebPMultARGBRows((uint8_t*)pic->argb, pic->argb_stride * sizeof(*pic->argb),
195 pic->width, pic->height, inverse);
196 }
197
AlphaMultiplyY(WebPPicture * const pic,int inverse)198 static void AlphaMultiplyY(WebPPicture* const pic, int inverse) {
199 if (pic->a != NULL) {
200 WebPMultRows(pic->y, pic->y_stride, pic->a, pic->a_stride,
201 pic->width, pic->height, inverse);
202 }
203 }
204
WebPPictureRescale(WebPPicture * picture,int width,int height)205 int WebPPictureRescale(WebPPicture* picture, int width, int height) {
206 WebPPicture tmp;
207 int prev_width, prev_height;
208 rescaler_t* work;
209
210 if (picture == NULL) return 0;
211 prev_width = picture->width;
212 prev_height = picture->height;
213 if (!WebPRescalerGetScaledDimensions(
214 prev_width, prev_height, &width, &height)) {
215 return 0;
216 }
217
218 PictureGrabSpecs(picture, &tmp);
219 tmp.width = width;
220 tmp.height = height;
221 if (!WebPPictureAlloc(&tmp)) return 0;
222
223 if (!picture->use_argb) {
224 work = (rescaler_t*)WebPSafeMalloc(2ULL * width, sizeof(*work));
225 if (work == NULL) {
226 WebPPictureFree(&tmp);
227 return 0;
228 }
229 // If present, we need to rescale alpha first (for AlphaMultiplyY).
230 if (picture->a != NULL) {
231 WebPInitAlphaProcessing();
232 if (!RescalePlane(picture->a, prev_width, prev_height, picture->a_stride,
233 tmp.a, width, height, tmp.a_stride, work, 1)) {
234 return 0;
235 }
236 }
237
238 // We take transparency into account on the luma plane only. That's not
239 // totally exact blending, but still is a good approximation.
240 AlphaMultiplyY(picture, 0);
241 if (!RescalePlane(picture->y, prev_width, prev_height, picture->y_stride,
242 tmp.y, width, height, tmp.y_stride, work, 1) ||
243 !RescalePlane(picture->u, HALVE(prev_width), HALVE(prev_height),
244 picture->uv_stride, tmp.u, HALVE(width), HALVE(height),
245 tmp.uv_stride, work, 1) ||
246 !RescalePlane(picture->v, HALVE(prev_width), HALVE(prev_height),
247 picture->uv_stride, tmp.v, HALVE(width), HALVE(height),
248 tmp.uv_stride, work, 1)) {
249 return 0;
250 }
251 AlphaMultiplyY(&tmp, 1);
252 } else {
253 work = (rescaler_t*)WebPSafeMalloc(2ULL * width * 4, sizeof(*work));
254 if (work == NULL) {
255 WebPPictureFree(&tmp);
256 return 0;
257 }
258 // In order to correctly interpolate colors, we need to apply the alpha
259 // weighting first (black-matting), scale the RGB values, and remove
260 // the premultiplication afterward (while preserving the alpha channel).
261 WebPInitAlphaProcessing();
262 AlphaMultiplyARGB(picture, 0);
263 if (!RescalePlane((const uint8_t*)picture->argb, prev_width, prev_height,
264 picture->argb_stride * 4, (uint8_t*)tmp.argb, width,
265 height, tmp.argb_stride * 4, work, 4)) {
266 return 0;
267 }
268 AlphaMultiplyARGB(&tmp, 1);
269 }
270 WebPPictureFree(picture);
271 WebPSafeFree(work);
272 *picture = tmp;
273 return 1;
274 }
275
276 #else // defined(WEBP_REDUCE_SIZE)
277
WebPPictureCopy(const WebPPicture * src,WebPPicture * dst)278 int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst) {
279 (void)src;
280 (void)dst;
281 return 0;
282 }
283
WebPPictureCrop(WebPPicture * pic,int left,int top,int width,int height)284 int WebPPictureCrop(WebPPicture* pic,
285 int left, int top, int width, int height) {
286 (void)pic;
287 (void)left;
288 (void)top;
289 (void)width;
290 (void)height;
291 return 0;
292 }
293
WebPPictureRescale(WebPPicture * pic,int width,int height)294 int WebPPictureRescale(WebPPicture* pic, int width, int height) {
295 (void)pic;
296 (void)width;
297 (void)height;
298 return 0;
299 }
300 #endif // !defined(WEBP_REDUCE_SIZE)
301