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 <assert.h>
15 #include <stdlib.h>
16
17 #include "./vp8enci.h"
18 #include "../utils/rescaler.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.
PictureGrabSpecs(const WebPPicture * const src,WebPPicture * const dst)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.
SnapTopLeftPosition(const WebPPicture * const pic,int * const left,int * const top)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.
AdjustAndCheckRectangle(const WebPPicture * const pic,int * const left,int * const top,int width,int height)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
WebPPictureCopy(const WebPPicture * src,WebPPicture * dst)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
WebPPictureIsView(const WebPPicture * picture)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
WebPPictureView(const WebPPicture * src,int left,int top,int width,int height,WebPPicture * dst)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
WebPPictureCrop(WebPPicture * pic,int left,int top,int width,int height)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
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)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
AlphaMultiplyARGB(WebPPicture * const pic,int inverse)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
AlphaMultiplyY(WebPPicture * const pic,int inverse)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
WebPPictureRescale(WebPPicture * pic,int width,int height)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