Png.cpp revision 1ab598f46c3ff520a67f9d80194847741f3467ab
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "util/BigBuffer.h"
18#include "Png.h"
19#include "Source.h"
20#include "util/Util.h"
21
22#include <androidfw/ResourceTypes.h>
23#include <iostream>
24#include <png.h>
25#include <sstream>
26#include <string>
27#include <vector>
28#include <zlib.h>
29
30namespace aapt {
31
32constexpr bool kDebug = false;
33constexpr size_t kPngSignatureSize = 8u;
34
35struct PngInfo {
36    ~PngInfo() {
37        for (png_bytep row : rows) {
38            if (row != nullptr) {
39                delete[] row;
40            }
41        }
42
43        delete[] xDivs;
44        delete[] yDivs;
45    }
46
47    void* serialize9Patch() {
48        void* serialized = android::Res_png_9patch::serialize(info9Patch, xDivs, yDivs,
49                                                              colors.data());
50        reinterpret_cast<android::Res_png_9patch*>(serialized)->deviceToFile();
51        return serialized;
52    }
53
54    uint32_t width = 0;
55    uint32_t height = 0;
56    std::vector<png_bytep> rows;
57
58    bool is9Patch = false;
59    android::Res_png_9patch info9Patch;
60    int32_t* xDivs = nullptr;
61    int32_t* yDivs = nullptr;
62    std::vector<uint32_t> colors;
63
64    // Layout padding.
65    bool haveLayoutBounds = false;
66    int32_t layoutBoundsLeft;
67    int32_t layoutBoundsTop;
68    int32_t layoutBoundsRight;
69    int32_t layoutBoundsBottom;
70
71    // Round rect outline description.
72    int32_t outlineInsetsLeft;
73    int32_t outlineInsetsTop;
74    int32_t outlineInsetsRight;
75    int32_t outlineInsetsBottom;
76    float outlineRadius;
77    uint8_t outlineAlpha;
78};
79
80static void readDataFromStream(png_structp readPtr, png_bytep data, png_size_t length) {
81    std::istream* input = reinterpret_cast<std::istream*>(png_get_io_ptr(readPtr));
82    if (!input->read(reinterpret_cast<char*>(data), length)) {
83        png_error(readPtr, strerror(errno));
84    }
85}
86
87static void writeDataToStream(png_structp writePtr, png_bytep data, png_size_t length) {
88    BigBuffer* outBuffer = reinterpret_cast<BigBuffer*>(png_get_io_ptr(writePtr));
89    png_bytep buf = outBuffer->nextBlock<png_byte>(length);
90    memcpy(buf, data, length);
91}
92
93static void flushDataToStream(png_structp /*writePtr*/) {
94}
95
96static void logWarning(png_structp readPtr, png_const_charp warningMessage) {
97    IDiagnostics* diag = reinterpret_cast<IDiagnostics*>(png_get_error_ptr(readPtr));
98    diag->warn(DiagMessage() << warningMessage);
99}
100
101
102static bool readPng(IDiagnostics* diag, png_structp readPtr, png_infop infoPtr, PngInfo* outInfo) {
103    if (setjmp(png_jmpbuf(readPtr))) {
104        diag->error(DiagMessage() << "failed reading png");
105        return false;
106    }
107
108    png_set_sig_bytes(readPtr, kPngSignatureSize);
109    png_read_info(readPtr, infoPtr);
110
111    int colorType, bitDepth, interlaceType, compressionType;
112    png_get_IHDR(readPtr, infoPtr, &outInfo->width, &outInfo->height, &bitDepth, &colorType,
113                 &interlaceType, &compressionType, nullptr);
114
115    if (colorType == PNG_COLOR_TYPE_PALETTE) {
116        png_set_palette_to_rgb(readPtr);
117    }
118
119    if (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8) {
120        png_set_expand_gray_1_2_4_to_8(readPtr);
121    }
122
123    if (png_get_valid(readPtr, infoPtr, PNG_INFO_tRNS)) {
124        png_set_tRNS_to_alpha(readPtr);
125    }
126
127    if (bitDepth == 16) {
128        png_set_strip_16(readPtr);
129    }
130
131    if (!(colorType & PNG_COLOR_MASK_ALPHA)) {
132        png_set_add_alpha(readPtr, 0xFF, PNG_FILLER_AFTER);
133    }
134
135    if (colorType == PNG_COLOR_TYPE_GRAY || colorType == PNG_COLOR_TYPE_GRAY_ALPHA) {
136        png_set_gray_to_rgb(readPtr);
137    }
138
139    png_set_interlace_handling(readPtr);
140    png_read_update_info(readPtr, infoPtr);
141
142    const uint32_t rowBytes = png_get_rowbytes(readPtr, infoPtr);
143    outInfo->rows.resize(outInfo->height);
144    for (size_t i = 0; i < outInfo->height; i++) {
145        outInfo->rows[i] = new png_byte[rowBytes];
146    }
147
148    png_read_image(readPtr, outInfo->rows.data());
149    png_read_end(readPtr, infoPtr);
150    return true;
151}
152
153static void checkNinePatchSerialization(android::Res_png_9patch* inPatch,  void* data) {
154    size_t patchSize = inPatch->serializedSize();
155    void* newData = malloc(patchSize);
156    memcpy(newData, data, patchSize);
157    android::Res_png_9patch* outPatch = inPatch->deserialize(newData);
158    outPatch->fileToDevice();
159    // deserialization is done in place, so outPatch == newData
160    assert(outPatch == newData);
161    assert(outPatch->numXDivs == inPatch->numXDivs);
162    assert(outPatch->numYDivs == inPatch->numYDivs);
163    assert(outPatch->paddingLeft == inPatch->paddingLeft);
164    assert(outPatch->paddingRight == inPatch->paddingRight);
165    assert(outPatch->paddingTop == inPatch->paddingTop);
166    assert(outPatch->paddingBottom == inPatch->paddingBottom);
167/*    for (int i = 0; i < outPatch->numXDivs; i++) {
168        assert(outPatch->getXDivs()[i] == inPatch->getXDivs()[i]);
169    }
170    for (int i = 0; i < outPatch->numYDivs; i++) {
171        assert(outPatch->getYDivs()[i] == inPatch->getYDivs()[i]);
172    }
173    for (int i = 0; i < outPatch->numColors; i++) {
174        assert(outPatch->getColors()[i] == inPatch->getColors()[i]);
175    }*/
176    free(newData);
177}
178
179/*static void dump_image(int w, int h, const png_byte* const* rows, int color_type) {
180    int i, j, rr, gg, bb, aa;
181
182    int bpp;
183    if (color_type == PNG_COLOR_TYPE_PALETTE || color_type == PNG_COLOR_TYPE_GRAY) {
184        bpp = 1;
185    } else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
186        bpp = 2;
187    } else if (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
188        // We use a padding byte even when there is no alpha
189        bpp = 4;
190    } else {
191        printf("Unknown color type %d.\n", color_type);
192    }
193
194    for (j = 0; j < h; j++) {
195        const png_byte* row = rows[j];
196        for (i = 0; i < w; i++) {
197            rr = row[0];
198            gg = row[1];
199            bb = row[2];
200            aa = row[3];
201            row += bpp;
202
203            if (i == 0) {
204                printf("Row %d:", j);
205            }
206            switch (bpp) {
207            case 1:
208                printf(" (%d)", rr);
209                break;
210            case 2:
211                printf(" (%d %d", rr, gg);
212                break;
213            case 3:
214                printf(" (%d %d %d)", rr, gg, bb);
215                break;
216            case 4:
217                printf(" (%d %d %d %d)", rr, gg, bb, aa);
218                break;
219            }
220            if (i == (w - 1)) {
221                printf("\n");
222            }
223        }
224    }
225}*/
226
227#define MAX(a,b) ((a)>(b)?(a):(b))
228#define ABS(a)   ((a)<0?-(a):(a))
229
230static void analyze_image(IDiagnostics* diag, const PngInfo& imageInfo, int grayscaleTolerance,
231                          png_colorp rgbPalette, png_bytep alphaPalette,
232                          int *paletteEntries, bool *hasTransparency, int *colorType,
233                          png_bytepp outRows) {
234    int w = imageInfo.width;
235    int h = imageInfo.height;
236    int i, j, rr, gg, bb, aa, idx;
237    uint32_t colors[256], col;
238    int num_colors = 0;
239    int maxGrayDeviation = 0;
240
241    bool isOpaque = true;
242    bool isPalette = true;
243    bool isGrayscale = true;
244
245    // Scan the entire image and determine if:
246    // 1. Every pixel has R == G == B (grayscale)
247    // 2. Every pixel has A == 255 (opaque)
248    // 3. There are no more than 256 distinct RGBA colors
249
250    if (kDebug) {
251        printf("Initial image data:\n");
252        //dump_image(w, h, imageInfo.rows.data(), PNG_COLOR_TYPE_RGB_ALPHA);
253    }
254
255    for (j = 0; j < h; j++) {
256        const png_byte* row = imageInfo.rows[j];
257        png_bytep out = outRows[j];
258        for (i = 0; i < w; i++) {
259            rr = *row++;
260            gg = *row++;
261            bb = *row++;
262            aa = *row++;
263
264            int odev = maxGrayDeviation;
265            maxGrayDeviation = MAX(ABS(rr - gg), maxGrayDeviation);
266            maxGrayDeviation = MAX(ABS(gg - bb), maxGrayDeviation);
267            maxGrayDeviation = MAX(ABS(bb - rr), maxGrayDeviation);
268            if (maxGrayDeviation > odev) {
269                if (kDebug) {
270                    printf("New max dev. = %d at pixel (%d, %d) = (%d %d %d %d)\n",
271                            maxGrayDeviation, i, j, rr, gg, bb, aa);
272                }
273            }
274
275            // Check if image is really grayscale
276            if (isGrayscale) {
277                if (rr != gg || rr != bb) {
278                    if (kDebug) {
279                        printf("Found a non-gray pixel at %d, %d = (%d %d %d %d)\n",
280                                i, j, rr, gg, bb, aa);
281                    }
282                    isGrayscale = false;
283                }
284            }
285
286            // Check if image is really opaque
287            if (isOpaque) {
288                if (aa != 0xff) {
289                    if (kDebug) {
290                        printf("Found a non-opaque pixel at %d, %d = (%d %d %d %d)\n",
291                                i, j, rr, gg, bb, aa);
292                    }
293                    isOpaque = false;
294                }
295            }
296
297            // Check if image is really <= 256 colors
298            if (isPalette) {
299                col = (uint32_t) ((rr << 24) | (gg << 16) | (bb << 8) | aa);
300                bool match = false;
301                for (idx = 0; idx < num_colors; idx++) {
302                    if (colors[idx] == col) {
303                        match = true;
304                        break;
305                    }
306                }
307
308                // Write the palette index for the pixel to outRows optimistically
309                // We might overwrite it later if we decide to encode as gray or
310                // gray + alpha
311                *out++ = idx;
312                if (!match) {
313                    if (num_colors == 256) {
314                        if (kDebug) {
315                            printf("Found 257th color at %d, %d\n", i, j);
316                        }
317                        isPalette = false;
318                    } else {
319                        colors[num_colors++] = col;
320                    }
321                }
322            }
323        }
324    }
325
326    *paletteEntries = 0;
327    *hasTransparency = !isOpaque;
328    int bpp = isOpaque ? 3 : 4;
329    int paletteSize = w * h + bpp * num_colors;
330
331    if (kDebug) {
332        printf("isGrayscale = %s\n", isGrayscale ? "true" : "false");
333        printf("isOpaque = %s\n", isOpaque ? "true" : "false");
334        printf("isPalette = %s\n", isPalette ? "true" : "false");
335        printf("Size w/ palette = %d, gray+alpha = %d, rgb(a) = %d\n",
336                paletteSize, 2 * w * h, bpp * w * h);
337        printf("Max gray deviation = %d, tolerance = %d\n", maxGrayDeviation, grayscaleTolerance);
338    }
339
340    // Choose the best color type for the image.
341    // 1. Opaque gray - use COLOR_TYPE_GRAY at 1 byte/pixel
342    // 2. Gray + alpha - use COLOR_TYPE_PALETTE if the number of distinct combinations
343    //     is sufficiently small, otherwise use COLOR_TYPE_GRAY_ALPHA
344    // 3. RGB(A) - use COLOR_TYPE_PALETTE if the number of distinct colors is sufficiently
345    //     small, otherwise use COLOR_TYPE_RGB{_ALPHA}
346    if (isGrayscale) {
347        if (isOpaque) {
348            *colorType = PNG_COLOR_TYPE_GRAY; // 1 byte/pixel
349        } else {
350            // Use a simple heuristic to determine whether using a palette will
351            // save space versus using gray + alpha for each pixel.
352            // This doesn't take into account chunk overhead, filtering, LZ
353            // compression, etc.
354            if (isPalette && (paletteSize < 2 * w * h)) {
355                *colorType = PNG_COLOR_TYPE_PALETTE; // 1 byte/pixel + 4 bytes/color
356            } else {
357                *colorType = PNG_COLOR_TYPE_GRAY_ALPHA; // 2 bytes per pixel
358            }
359        }
360    } else if (isPalette && (paletteSize < bpp * w * h)) {
361        *colorType = PNG_COLOR_TYPE_PALETTE;
362    } else {
363        if (maxGrayDeviation <= grayscaleTolerance) {
364            diag->note(DiagMessage()
365                       << "forcing image to gray (max deviation = "
366                       << maxGrayDeviation << ")");
367            *colorType = isOpaque ? PNG_COLOR_TYPE_GRAY : PNG_COLOR_TYPE_GRAY_ALPHA;
368        } else {
369            *colorType = isOpaque ? PNG_COLOR_TYPE_RGB : PNG_COLOR_TYPE_RGB_ALPHA;
370        }
371    }
372
373    // Perform postprocessing of the image or palette data based on the final
374    // color type chosen
375
376    if (*colorType == PNG_COLOR_TYPE_PALETTE) {
377        // Create separate RGB and Alpha palettes and set the number of colors
378        *paletteEntries = num_colors;
379
380        // Create the RGB and alpha palettes
381        for (int idx = 0; idx < num_colors; idx++) {
382            col = colors[idx];
383            rgbPalette[idx].red   = (png_byte) ((col >> 24) & 0xff);
384            rgbPalette[idx].green = (png_byte) ((col >> 16) & 0xff);
385            rgbPalette[idx].blue  = (png_byte) ((col >>  8) & 0xff);
386            alphaPalette[idx]     = (png_byte)  (col        & 0xff);
387        }
388    } else if (*colorType == PNG_COLOR_TYPE_GRAY || *colorType == PNG_COLOR_TYPE_GRAY_ALPHA) {
389        // If the image is gray or gray + alpha, compact the pixels into outRows
390        for (j = 0; j < h; j++) {
391            const png_byte* row = imageInfo.rows[j];
392            png_bytep out = outRows[j];
393            for (i = 0; i < w; i++) {
394                rr = *row++;
395                gg = *row++;
396                bb = *row++;
397                aa = *row++;
398
399                if (isGrayscale) {
400                    *out++ = rr;
401                } else {
402                    *out++ = (png_byte) (rr * 0.2126f + gg * 0.7152f + bb * 0.0722f);
403                }
404                if (!isOpaque) {
405                    *out++ = aa;
406                }
407           }
408        }
409    }
410}
411
412static bool writePng(IDiagnostics* diag, png_structp writePtr, png_infop infoPtr, PngInfo* info,
413                     int grayScaleTolerance) {
414    if (setjmp(png_jmpbuf(writePtr))) {
415        diag->error(DiagMessage() << "failed to write png");
416        return false;
417    }
418
419    uint32_t width, height;
420    int colorType, bitDepth, interlaceType, compressionType;
421
422    png_unknown_chunk unknowns[3];
423    unknowns[0].data = nullptr;
424    unknowns[1].data = nullptr;
425    unknowns[2].data = nullptr;
426
427    png_bytepp outRows = (png_bytepp) malloc((int) info->height * sizeof(png_bytep));
428    if (outRows == (png_bytepp) 0) {
429        printf("Can't allocate output buffer!\n");
430        exit(1);
431    }
432    for (uint32_t i = 0; i < info->height; i++) {
433        outRows[i] = (png_bytep) malloc(2 * (int) info->width);
434        if (outRows[i] == (png_bytep) 0) {
435            printf("Can't allocate output buffer!\n");
436            exit(1);
437        }
438    }
439
440    png_set_compression_level(writePtr, Z_BEST_COMPRESSION);
441
442    if (kDebug) {
443        diag->note(DiagMessage()
444                   << "writing image: w = " << info->width
445                   << ", h = " << info->height);
446    }
447
448    png_color rgbPalette[256];
449    png_byte alphaPalette[256];
450    bool hasTransparency;
451    int paletteEntries;
452
453    analyze_image(diag, *info, grayScaleTolerance, rgbPalette, alphaPalette,
454                  &paletteEntries, &hasTransparency, &colorType, outRows);
455
456    // If the image is a 9-patch, we need to preserve it as a ARGB file to make
457    // sure the pixels will not be pre-dithered/clamped until we decide they are
458    if (info->is9Patch && (colorType == PNG_COLOR_TYPE_RGB ||
459            colorType == PNG_COLOR_TYPE_GRAY || colorType == PNG_COLOR_TYPE_PALETTE)) {
460        colorType = PNG_COLOR_TYPE_RGB_ALPHA;
461    }
462
463    if (kDebug) {
464        switch (colorType) {
465        case PNG_COLOR_TYPE_PALETTE:
466            diag->note(DiagMessage()
467                       << "has " << paletteEntries
468                       << " colors" << (hasTransparency ? " (with alpha)" : "")
469                       << ", using PNG_COLOR_TYPE_PALLETTE");
470            break;
471        case PNG_COLOR_TYPE_GRAY:
472            diag->note(DiagMessage() << "is opaque gray, using PNG_COLOR_TYPE_GRAY");
473            break;
474        case PNG_COLOR_TYPE_GRAY_ALPHA:
475            diag->note(DiagMessage() << "is gray + alpha, using PNG_COLOR_TYPE_GRAY_ALPHA");
476            break;
477        case PNG_COLOR_TYPE_RGB:
478            diag->note(DiagMessage() << "is opaque RGB, using PNG_COLOR_TYPE_RGB");
479            break;
480        case PNG_COLOR_TYPE_RGB_ALPHA:
481            diag->note(DiagMessage() << "is RGB + alpha, using PNG_COLOR_TYPE_RGB_ALPHA");
482            break;
483        }
484    }
485
486    png_set_IHDR(writePtr, infoPtr, info->width, info->height, 8, colorType,
487                 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
488
489    if (colorType == PNG_COLOR_TYPE_PALETTE) {
490        png_set_PLTE(writePtr, infoPtr, rgbPalette, paletteEntries);
491        if (hasTransparency) {
492            png_set_tRNS(writePtr, infoPtr, alphaPalette, paletteEntries, (png_color_16p) 0);
493        }
494        png_set_filter(writePtr, 0, PNG_NO_FILTERS);
495    } else {
496        png_set_filter(writePtr, 0, PNG_ALL_FILTERS);
497    }
498
499    if (info->is9Patch) {
500        int chunkCount = 2 + (info->haveLayoutBounds ? 1 : 0);
501        int pIndex = info->haveLayoutBounds ? 2 : 1;
502        int bIndex = 1;
503        int oIndex = 0;
504
505        // Chunks ordered thusly because older platforms depend on the base 9 patch data being last
506        png_bytep chunkNames = info->haveLayoutBounds
507                ? (png_bytep)"npOl\0npLb\0npTc\0"
508                : (png_bytep)"npOl\0npTc";
509
510        // base 9 patch data
511        if (kDebug) {
512            diag->note(DiagMessage() << "adding 9-patch info..");
513        }
514        strcpy((char*)unknowns[pIndex].name, "npTc");
515        unknowns[pIndex].data = (png_byte*) info->serialize9Patch();
516        unknowns[pIndex].size = info->info9Patch.serializedSize();
517        // TODO: remove the check below when everything works
518        checkNinePatchSerialization(&info->info9Patch, unknowns[pIndex].data);
519
520        // automatically generated 9 patch outline data
521        int chunkSize = sizeof(png_uint_32) * 6;
522        strcpy((char*)unknowns[oIndex].name, "npOl");
523        unknowns[oIndex].data = (png_byte*) calloc(chunkSize, 1);
524        png_byte outputData[chunkSize];
525        memcpy(&outputData, &info->outlineInsetsLeft, 4 * sizeof(png_uint_32));
526        ((float*) outputData)[4] = info->outlineRadius;
527        ((png_uint_32*) outputData)[5] = info->outlineAlpha;
528        memcpy(unknowns[oIndex].data, &outputData, chunkSize);
529        unknowns[oIndex].size = chunkSize;
530
531        // optional optical inset / layout bounds data
532        if (info->haveLayoutBounds) {
533            int chunkSize = sizeof(png_uint_32) * 4;
534            strcpy((char*)unknowns[bIndex].name, "npLb");
535            unknowns[bIndex].data = (png_byte*) calloc(chunkSize, 1);
536            memcpy(unknowns[bIndex].data, &info->layoutBoundsLeft, chunkSize);
537            unknowns[bIndex].size = chunkSize;
538        }
539
540        for (int i = 0; i < chunkCount; i++) {
541            unknowns[i].location = PNG_HAVE_PLTE;
542        }
543        png_set_keep_unknown_chunks(writePtr, PNG_HANDLE_CHUNK_ALWAYS,
544                                    chunkNames, chunkCount);
545        png_set_unknown_chunks(writePtr, infoPtr, unknowns, chunkCount);
546
547#if PNG_LIBPNG_VER < 10600
548        // Deal with unknown chunk location bug in 1.5.x and earlier.
549        png_set_unknown_chunk_location(writePtr, infoPtr, 0, PNG_HAVE_PLTE);
550        if (info->haveLayoutBounds) {
551            png_set_unknown_chunk_location(writePtr, infoPtr, 1, PNG_HAVE_PLTE);
552        }
553#endif
554    }
555
556    png_write_info(writePtr, infoPtr);
557
558    png_bytepp rows;
559    if (colorType == PNG_COLOR_TYPE_RGB || colorType == PNG_COLOR_TYPE_RGB_ALPHA) {
560        if (colorType == PNG_COLOR_TYPE_RGB) {
561            png_set_filler(writePtr, 0, PNG_FILLER_AFTER);
562        }
563        rows = info->rows.data();
564    } else {
565        rows = outRows;
566    }
567    png_write_image(writePtr, rows);
568
569    if (kDebug) {
570        printf("Final image data:\n");
571        //dump_image(info->width, info->height, rows, colorType);
572    }
573
574    png_write_end(writePtr, infoPtr);
575
576    for (uint32_t i = 0; i < info->height; i++) {
577        free(outRows[i]);
578    }
579    free(outRows);
580    free(unknowns[0].data);
581    free(unknowns[1].data);
582    free(unknowns[2].data);
583
584    png_get_IHDR(writePtr, infoPtr, &width, &height, &bitDepth, &colorType, &interlaceType,
585                 &compressionType, nullptr);
586
587    if (kDebug) {
588        diag->note(DiagMessage()
589                   << "image written: w = " << width << ", h = " << height
590                   << ", d = " << bitDepth << ", colors = " << colorType
591                   << ", inter = " << interlaceType << ", comp = " << compressionType);
592    }
593    return true;
594}
595
596constexpr uint32_t kColorWhite = 0xffffffffu;
597constexpr uint32_t kColorTick = 0xff000000u;
598constexpr uint32_t kColorLayoutBoundsTick = 0xff0000ffu;
599
600enum class TickType {
601    kNone,
602    kTick,
603    kLayoutBounds,
604    kBoth
605};
606
607static TickType tickType(png_bytep p, bool transparent, const char** outError) {
608    png_uint_32 color = p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
609
610    if (transparent) {
611        if (p[3] == 0) {
612            return TickType::kNone;
613        }
614        if (color == kColorLayoutBoundsTick) {
615            return TickType::kLayoutBounds;
616        }
617        if (color == kColorTick) {
618            return TickType::kTick;
619        }
620
621        // Error cases
622        if (p[3] != 0xff) {
623            *outError = "Frame pixels must be either solid or transparent "
624                        "(not intermediate alphas)";
625            return TickType::kNone;
626        }
627
628        if (p[0] != 0 || p[1] != 0 || p[2] != 0) {
629            *outError = "Ticks in transparent frame must be black or red";
630        }
631        return TickType::kTick;
632    }
633
634    if (p[3] != 0xFF) {
635        *outError = "White frame must be a solid color (no alpha)";
636    }
637    if (color == kColorWhite) {
638        return TickType::kNone;
639    }
640    if (color == kColorTick) {
641        return TickType::kTick;
642    }
643    if (color == kColorLayoutBoundsTick) {
644        return TickType::kLayoutBounds;
645    }
646
647    if (p[0] != 0 || p[1] != 0 || p[2] != 0) {
648        *outError = "Ticks in white frame must be black or red";
649        return TickType::kNone;
650    }
651    return TickType::kTick;
652}
653
654enum class TickState {
655    kStart,
656    kInside1,
657    kOutside1
658};
659
660static bool getHorizontalTicks(png_bytep row, int width, bool transparent, bool required,
661                               int32_t* outLeft, int32_t* outRight, const char** outError,
662                               uint8_t* outDivs, bool multipleAllowed) {
663    *outLeft = *outRight = -1;
664    TickState state = TickState::kStart;
665    bool found = false;
666
667    for (int i = 1; i < width - 1; i++) {
668        if (tickType(row+i*4, transparent, outError) == TickType::kTick) {
669            if (state == TickState::kStart ||
670                (state == TickState::kOutside1 && multipleAllowed)) {
671                *outLeft = i-1;
672                *outRight = width-2;
673                found = true;
674                if (outDivs != NULL) {
675                    *outDivs += 2;
676                }
677                state = TickState::kInside1;
678            } else if (state == TickState::kOutside1) {
679                *outError = "Can't have more than one marked region along edge";
680                *outLeft = i;
681                return false;
682            }
683        } else if (!*outError) {
684            if (state == TickState::kInside1) {
685                // We're done with this div.  Move on to the next.
686                *outRight = i-1;
687                outRight += 2;
688                outLeft += 2;
689                state = TickState::kOutside1;
690            }
691        } else {
692            *outLeft = i;
693            return false;
694        }
695    }
696
697    if (required && !found) {
698        *outError = "No marked region found along edge";
699        *outLeft = -1;
700        return false;
701    }
702    return true;
703}
704
705static bool getVerticalTicks(png_bytepp rows, int offset, int height, bool transparent,
706                             bool required, int32_t* outTop, int32_t* outBottom,
707                             const char** outError, uint8_t* outDivs, bool multipleAllowed) {
708    *outTop = *outBottom = -1;
709    TickState state = TickState::kStart;
710    bool found = false;
711
712    for (int i = 1; i < height - 1; i++) {
713        if (tickType(rows[i]+offset, transparent, outError) == TickType::kTick) {
714            if (state == TickState::kStart ||
715                (state == TickState::kOutside1 && multipleAllowed)) {
716                *outTop = i-1;
717                *outBottom = height-2;
718                found = true;
719                if (outDivs != NULL) {
720                    *outDivs += 2;
721                }
722                state = TickState::kInside1;
723            } else if (state == TickState::kOutside1) {
724                *outError = "Can't have more than one marked region along edge";
725                *outTop = i;
726                return false;
727            }
728        } else if (!*outError) {
729            if (state == TickState::kInside1) {
730                // We're done with this div.  Move on to the next.
731                *outBottom = i-1;
732                outTop += 2;
733                outBottom += 2;
734                state = TickState::kOutside1;
735            }
736        } else {
737            *outTop = i;
738            return false;
739        }
740    }
741
742    if (required && !found) {
743        *outError = "No marked region found along edge";
744        *outTop = -1;
745        return false;
746    }
747    return true;
748}
749
750static bool getHorizontalLayoutBoundsTicks(png_bytep row, int width, bool transparent,
751                                           bool /* required */, int32_t* outLeft,
752                                           int32_t* outRight, const char** outError) {
753    *outLeft = *outRight = 0;
754
755    // Look for left tick
756    if (tickType(row + 4, transparent, outError) == TickType::kLayoutBounds) {
757        // Starting with a layout padding tick
758        int i = 1;
759        while (i < width - 1) {
760            (*outLeft)++;
761            i++;
762            if (tickType(row + i * 4, transparent, outError) != TickType::kLayoutBounds) {
763                break;
764            }
765        }
766    }
767
768    // Look for right tick
769    if (tickType(row + (width - 2) * 4, transparent, outError) == TickType::kLayoutBounds) {
770        // Ending with a layout padding tick
771        int i = width - 2;
772        while (i > 1) {
773            (*outRight)++;
774            i--;
775            if (tickType(row+i*4, transparent, outError) != TickType::kLayoutBounds) {
776                break;
777            }
778        }
779    }
780    return true;
781}
782
783static bool getVerticalLayoutBoundsTicks(png_bytepp rows, int offset, int height, bool transparent,
784                                         bool /* required */, int32_t* outTop, int32_t* outBottom,
785                                         const char** outError) {
786    *outTop = *outBottom = 0;
787
788    // Look for top tick
789    if (tickType(rows[1] + offset, transparent, outError) == TickType::kLayoutBounds) {
790        // Starting with a layout padding tick
791        int i = 1;
792        while (i < height - 1) {
793            (*outTop)++;
794            i++;
795            if (tickType(rows[i] + offset, transparent, outError) != TickType::kLayoutBounds) {
796                break;
797            }
798        }
799    }
800
801    // Look for bottom tick
802    if (tickType(rows[height - 2] + offset, transparent, outError) == TickType::kLayoutBounds) {
803        // Ending with a layout padding tick
804        int i = height - 2;
805        while (i > 1) {
806            (*outBottom)++;
807            i--;
808            if (tickType(rows[i] + offset, transparent, outError) != TickType::kLayoutBounds) {
809                break;
810            }
811        }
812    }
813    return true;
814}
815
816static void findMaxOpacity(png_bytepp rows, int startX, int startY, int endX, int endY,
817                           int dX, int dY, int* outInset) {
818    uint8_t maxOpacity = 0;
819    int inset = 0;
820    *outInset = 0;
821    for (int x = startX, y = startY; x != endX && y != endY; x += dX, y += dY, inset++) {
822        png_byte* color = rows[y] + x * 4;
823        uint8_t opacity = color[3];
824        if (opacity > maxOpacity) {
825            maxOpacity = opacity;
826            *outInset = inset;
827        }
828        if (opacity == 0xff) return;
829    }
830}
831
832static uint8_t maxAlphaOverRow(png_bytep row, int startX, int endX) {
833    uint8_t maxAlpha = 0;
834    for (int x = startX; x < endX; x++) {
835        uint8_t alpha = (row + x * 4)[3];
836        if (alpha > maxAlpha) maxAlpha = alpha;
837    }
838    return maxAlpha;
839}
840
841static uint8_t maxAlphaOverCol(png_bytepp rows, int offsetX, int startY, int endY) {
842    uint8_t maxAlpha = 0;
843    for (int y = startY; y < endY; y++) {
844        uint8_t alpha = (rows[y] + offsetX * 4)[3];
845        if (alpha > maxAlpha) maxAlpha = alpha;
846    }
847    return maxAlpha;
848}
849
850static void getOutline(PngInfo* image) {
851    int midX = image->width / 2;
852    int midY = image->height / 2;
853    int endX = image->width - 2;
854    int endY = image->height - 2;
855
856    // find left and right extent of nine patch content on center row
857    if (image->width > 4) {
858        findMaxOpacity(image->rows.data(), 1, midY, midX, -1, 1, 0, &image->outlineInsetsLeft);
859        findMaxOpacity(image->rows.data(), endX, midY, midX, -1, -1, 0,
860                       &image->outlineInsetsRight);
861    } else {
862        image->outlineInsetsLeft = 0;
863        image->outlineInsetsRight = 0;
864    }
865
866    // find top and bottom extent of nine patch content on center column
867    if (image->height > 4) {
868        findMaxOpacity(image->rows.data(), midX, 1, -1, midY, 0, 1, &image->outlineInsetsTop);
869        findMaxOpacity(image->rows.data(), midX, endY, -1, midY, 0, -1,
870                       &image->outlineInsetsBottom);
871    } else {
872        image->outlineInsetsTop = 0;
873        image->outlineInsetsBottom = 0;
874    }
875
876    int innerStartX = 1 + image->outlineInsetsLeft;
877    int innerStartY = 1 + image->outlineInsetsTop;
878    int innerEndX = endX - image->outlineInsetsRight;
879    int innerEndY = endY - image->outlineInsetsBottom;
880    int innerMidX = (innerEndX + innerStartX) / 2;
881    int innerMidY = (innerEndY + innerStartY) / 2;
882
883    // assuming the image is a round rect, compute the radius by marching
884    // diagonally from the top left corner towards the center
885    image->outlineAlpha = std::max(
886            maxAlphaOverRow(image->rows[innerMidY], innerStartX, innerEndX),
887            maxAlphaOverCol(image->rows.data(), innerMidX, innerStartY, innerStartY));
888
889    int diagonalInset = 0;
890    findMaxOpacity(image->rows.data(), innerStartX, innerStartY, innerMidX, innerMidY, 1, 1,
891                   &diagonalInset);
892
893    /* Determine source radius based upon inset:
894     *     sqrt(r^2 + r^2) = sqrt(i^2 + i^2) + r
895     *     sqrt(2) * r = sqrt(2) * i + r
896     *     (sqrt(2) - 1) * r = sqrt(2) * i
897     *     r = sqrt(2) / (sqrt(2) - 1) * i
898     */
899    image->outlineRadius = 3.4142f * diagonalInset;
900
901    if (kDebug) {
902        printf("outline insets %d %d %d %d, rad %f, alpha %x\n",
903                image->outlineInsetsLeft,
904                image->outlineInsetsTop,
905                image->outlineInsetsRight,
906                image->outlineInsetsBottom,
907                image->outlineRadius,
908                image->outlineAlpha);
909    }
910}
911
912static uint32_t getColor(png_bytepp rows, int left, int top, int right, int bottom) {
913    png_bytep color = rows[top] + left*4;
914
915    if (left > right || top > bottom) {
916        return android::Res_png_9patch::TRANSPARENT_COLOR;
917    }
918
919    while (top <= bottom) {
920        for (int i = left; i <= right; i++) {
921            png_bytep p = rows[top]+i*4;
922            if (color[3] == 0) {
923                if (p[3] != 0) {
924                    return android::Res_png_9patch::NO_COLOR;
925                }
926            } else if (p[0] != color[0] || p[1] != color[1] ||
927                    p[2] != color[2] || p[3] != color[3]) {
928                return android::Res_png_9patch::NO_COLOR;
929            }
930        }
931        top++;
932    }
933
934    if (color[3] == 0) {
935        return android::Res_png_9patch::TRANSPARENT_COLOR;
936    }
937    return (color[3]<<24) | (color[0]<<16) | (color[1]<<8) | color[2];
938}
939
940static bool do9Patch(PngInfo* image, std::string* outError) {
941    image->is9Patch = true;
942
943    int W = image->width;
944    int H = image->height;
945    int i, j;
946
947    const int maxSizeXDivs = W * sizeof(int32_t);
948    const int maxSizeYDivs = H * sizeof(int32_t);
949    int32_t* xDivs = image->xDivs = new int32_t[W];
950    int32_t* yDivs = image->yDivs = new int32_t[H];
951    uint8_t numXDivs = 0;
952    uint8_t numYDivs = 0;
953
954    int8_t numColors;
955    int numRows;
956    int numCols;
957    int top;
958    int left;
959    int right;
960    int bottom;
961    memset(xDivs, -1, maxSizeXDivs);
962    memset(yDivs, -1, maxSizeYDivs);
963    image->info9Patch.paddingLeft = image->info9Patch.paddingRight = -1;
964    image->info9Patch.paddingTop = image->info9Patch.paddingBottom = -1;
965    image->layoutBoundsLeft = image->layoutBoundsRight = 0;
966    image->layoutBoundsTop = image->layoutBoundsBottom = 0;
967
968    png_bytep p = image->rows[0];
969    bool transparent = p[3] == 0;
970    bool hasColor = false;
971
972    const char* errorMsg = nullptr;
973    int errorPixel = -1;
974    const char* errorEdge = nullptr;
975
976    int colorIndex = 0;
977    std::vector<png_bytep> newRows;
978
979    // Validate size...
980    if (W < 3 || H < 3) {
981        errorMsg = "Image must be at least 3x3 (1x1 without frame) pixels";
982        goto getout;
983    }
984
985    // Validate frame...
986    if (!transparent &&
987            (p[0] != 0xFF || p[1] != 0xFF || p[2] != 0xFF || p[3] != 0xFF)) {
988        errorMsg = "Must have one-pixel frame that is either transparent or white";
989        goto getout;
990    }
991
992    // Find left and right of sizing areas...
993    if (!getHorizontalTicks(p, W, transparent, true, &xDivs[0], &xDivs[1], &errorMsg, &numXDivs,
994                            true)) {
995        errorPixel = xDivs[0];
996        errorEdge = "top";
997        goto getout;
998    }
999
1000    // Find top and bottom of sizing areas...
1001    if (!getVerticalTicks(image->rows.data(), 0, H, transparent, true, &yDivs[0], &yDivs[1],
1002                          &errorMsg, &numYDivs, true)) {
1003        errorPixel = yDivs[0];
1004        errorEdge = "left";
1005        goto getout;
1006    }
1007
1008    // Copy patch size data into image...
1009    image->info9Patch.numXDivs = numXDivs;
1010    image->info9Patch.numYDivs = numYDivs;
1011
1012    // Find left and right of padding area...
1013    if (!getHorizontalTicks(image->rows[H-1], W, transparent, false,
1014                            &image->info9Patch.paddingLeft, &image->info9Patch.paddingRight,
1015                            &errorMsg, nullptr, false)) {
1016        errorPixel = image->info9Patch.paddingLeft;
1017        errorEdge = "bottom";
1018        goto getout;
1019    }
1020
1021    // Find top and bottom of padding area...
1022    if (!getVerticalTicks(image->rows.data(), (W-1)*4, H, transparent, false,
1023                          &image->info9Patch.paddingTop, &image->info9Patch.paddingBottom,
1024                          &errorMsg, nullptr, false)) {
1025        errorPixel = image->info9Patch.paddingTop;
1026        errorEdge = "right";
1027        goto getout;
1028    }
1029
1030    // Find left and right of layout padding...
1031    getHorizontalLayoutBoundsTicks(image->rows[H-1], W, transparent, false,
1032                                   &image->layoutBoundsLeft, &image->layoutBoundsRight, &errorMsg);
1033
1034    getVerticalLayoutBoundsTicks(image->rows.data(), (W-1)*4, H, transparent, false,
1035                                 &image->layoutBoundsTop, &image->layoutBoundsBottom, &errorMsg);
1036
1037    image->haveLayoutBounds = image->layoutBoundsLeft != 0
1038                               || image->layoutBoundsRight != 0
1039                               || image->layoutBoundsTop != 0
1040                               || image->layoutBoundsBottom != 0;
1041
1042    if (image->haveLayoutBounds) {
1043        if (kDebug) {
1044            printf("layoutBounds=%d %d %d %d\n", image->layoutBoundsLeft, image->layoutBoundsTop,
1045                    image->layoutBoundsRight, image->layoutBoundsBottom);
1046        }
1047    }
1048
1049    // use opacity of pixels to estimate the round rect outline
1050    getOutline(image);
1051
1052    // If padding is not yet specified, take values from size.
1053    if (image->info9Patch.paddingLeft < 0) {
1054        image->info9Patch.paddingLeft = xDivs[0];
1055        image->info9Patch.paddingRight = W - 2 - xDivs[1];
1056    } else {
1057        // Adjust value to be correct!
1058        image->info9Patch.paddingRight = W - 2 - image->info9Patch.paddingRight;
1059    }
1060    if (image->info9Patch.paddingTop < 0) {
1061        image->info9Patch.paddingTop = yDivs[0];
1062        image->info9Patch.paddingBottom = H - 2 - yDivs[1];
1063    } else {
1064        // Adjust value to be correct!
1065        image->info9Patch.paddingBottom = H - 2 - image->info9Patch.paddingBottom;
1066    }
1067
1068/*    if (kDebug) {
1069        printf("Size ticks for %s: x0=%d, x1=%d, y0=%d, y1=%d\n", imageName,
1070                xDivs[0], xDivs[1],
1071                yDivs[0], yDivs[1]);
1072        printf("padding ticks for %s: l=%d, r=%d, t=%d, b=%d\n", imageName,
1073                image->info9Patch.paddingLeft, image->info9Patch.paddingRight,
1074                image->info9Patch.paddingTop, image->info9Patch.paddingBottom);
1075    }*/
1076
1077    // Remove frame from image.
1078    newRows.resize(H - 2);
1079    for (i = 0; i < H - 2; i++) {
1080        newRows[i] = image->rows[i + 1];
1081        memmove(newRows[i], newRows[i] + 4, (W - 2) * 4);
1082    }
1083    image->rows.swap(newRows);
1084
1085    image->width -= 2;
1086    W = image->width;
1087    image->height -= 2;
1088    H = image->height;
1089
1090    // Figure out the number of rows and columns in the N-patch
1091    numCols = numXDivs + 1;
1092    if (xDivs[0] == 0) {  // Column 1 is strechable
1093        numCols--;
1094    }
1095    if (xDivs[numXDivs - 1] == W) {
1096        numCols--;
1097    }
1098    numRows = numYDivs + 1;
1099    if (yDivs[0] == 0) {  // Row 1 is strechable
1100        numRows--;
1101    }
1102    if (yDivs[numYDivs - 1] == H) {
1103        numRows--;
1104    }
1105
1106    // Make sure the amount of rows and columns will fit in the number of
1107    // colors we can use in the 9-patch format.
1108    if (numRows * numCols > 0x7F) {
1109        errorMsg = "Too many rows and columns in 9-patch perimeter";
1110        goto getout;
1111    }
1112
1113    numColors = numRows * numCols;
1114    image->info9Patch.numColors = numColors;
1115    image->colors.resize(numColors);
1116
1117    // Fill in color information for each patch.
1118
1119    uint32_t c;
1120    top = 0;
1121
1122    // The first row always starts with the top being at y=0 and the bottom
1123    // being either yDivs[1] (if yDivs[0]=0) of yDivs[0].  In the former case
1124    // the first row is stretchable along the Y axis, otherwise it is fixed.
1125    // The last row always ends with the bottom being bitmap.height and the top
1126    // being either yDivs[numYDivs-2] (if yDivs[numYDivs-1]=bitmap.height) or
1127    // yDivs[numYDivs-1]. In the former case the last row is stretchable along
1128    // the Y axis, otherwise it is fixed.
1129    //
1130    // The first and last columns are similarly treated with respect to the X
1131    // axis.
1132    //
1133    // The above is to help explain some of the special casing that goes on the
1134    // code below.
1135
1136    // The initial yDiv and whether the first row is considered stretchable or
1137    // not depends on whether yDiv[0] was zero or not.
1138    for (j = (yDivs[0] == 0 ? 1 : 0); j <= numYDivs && top < H; j++) {
1139        if (j == numYDivs) {
1140            bottom = H;
1141        } else {
1142            bottom = yDivs[j];
1143        }
1144        left = 0;
1145        // The initial xDiv and whether the first column is considered
1146        // stretchable or not depends on whether xDiv[0] was zero or not.
1147        for (i = xDivs[0] == 0 ? 1 : 0; i <= numXDivs && left < W; i++) {
1148            if (i == numXDivs) {
1149                right = W;
1150            } else {
1151                right = xDivs[i];
1152            }
1153            c = getColor(image->rows.data(), left, top, right - 1, bottom - 1);
1154            image->colors[colorIndex++] = c;
1155            if (kDebug) {
1156                if (c != android::Res_png_9patch::NO_COLOR) {
1157                    hasColor = true;
1158                }
1159            }
1160            left = right;
1161        }
1162        top = bottom;
1163    }
1164
1165    assert(colorIndex == numColors);
1166
1167    if (kDebug && hasColor) {
1168        for (i = 0; i < numColors; i++) {
1169            if (i == 0) printf("Colors:\n");
1170            printf(" #%08x", image->colors[i]);
1171            if (i == numColors - 1) printf("\n");
1172        }
1173    }
1174getout:
1175    if (errorMsg) {
1176        std::stringstream err;
1177        err << "9-patch malformed: " << errorMsg;
1178        if (!errorEdge) {
1179            err << "." << std::endl;
1180            if (errorPixel >= 0) {
1181                err << "Found at pixel #" << errorPixel << " along " << errorEdge << " edge";
1182            } else {
1183                err << "Found along " << errorEdge << " edge";
1184            }
1185        }
1186        *outError = err.str();
1187        return false;
1188    }
1189    return true;
1190}
1191
1192
1193bool Png::process(const Source& source, std::istream* input, BigBuffer* outBuffer,
1194                  const PngOptions& options) {
1195    png_byte signature[kPngSignatureSize];
1196
1197    // Read the PNG signature first.
1198    if (!input->read(reinterpret_cast<char*>(signature), kPngSignatureSize)) {
1199        mDiag->error(DiagMessage() << strerror(errno));
1200        return false;
1201    }
1202
1203    // If the PNG signature doesn't match, bail early.
1204    if (png_sig_cmp(signature, 0, kPngSignatureSize) != 0) {
1205        mDiag->error(DiagMessage() << "not a valid png file");
1206        return false;
1207    }
1208
1209    bool result = false;
1210    png_structp readPtr = nullptr;
1211    png_infop infoPtr = nullptr;
1212    png_structp writePtr = nullptr;
1213    png_infop writeInfoPtr = nullptr;
1214    PngInfo pngInfo = {};
1215
1216    readPtr = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, nullptr, nullptr);
1217    if (!readPtr) {
1218        mDiag->error(DiagMessage() << "failed to allocate read ptr");
1219        goto bail;
1220    }
1221
1222    infoPtr = png_create_info_struct(readPtr);
1223    if (!infoPtr) {
1224        mDiag->error(DiagMessage() << "failed to allocate info ptr");
1225        goto bail;
1226    }
1227
1228    png_set_error_fn(readPtr, reinterpret_cast<png_voidp>(mDiag), nullptr, logWarning);
1229
1230    // Set the read function to read from std::istream.
1231    png_set_read_fn(readPtr, (png_voidp) input, readDataFromStream);
1232
1233    if (!readPng(mDiag, readPtr, infoPtr, &pngInfo)) {
1234        goto bail;
1235    }
1236
1237    if (util::stringEndsWith<char>(source.path, ".9.png")) {
1238        std::string errorMsg;
1239        if (!do9Patch(&pngInfo, &errorMsg)) {
1240            mDiag->error(DiagMessage() << errorMsg);
1241            goto bail;
1242        }
1243    }
1244
1245    writePtr = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, nullptr, nullptr);
1246    if (!writePtr) {
1247        mDiag->error(DiagMessage() << "failed to allocate write ptr");
1248        goto bail;
1249    }
1250
1251    writeInfoPtr = png_create_info_struct(writePtr);
1252    if (!writeInfoPtr) {
1253        mDiag->error(DiagMessage() << "failed to allocate write info ptr");
1254        goto bail;
1255    }
1256
1257    png_set_error_fn(writePtr, nullptr, nullptr, logWarning);
1258
1259    // Set the write function to write to std::ostream.
1260    png_set_write_fn(writePtr, (png_voidp)outBuffer, writeDataToStream, flushDataToStream);
1261
1262    if (!writePng(mDiag, writePtr, writeInfoPtr, &pngInfo, options.grayScaleTolerance)) {
1263        goto bail;
1264    }
1265
1266    result = true;
1267bail:
1268    if (readPtr) {
1269        png_destroy_read_struct(&readPtr, &infoPtr, nullptr);
1270    }
1271
1272    if (writePtr) {
1273        png_destroy_write_struct(&writePtr, &writeInfoPtr);
1274    }
1275    return result;
1276}
1277
1278} // namespace aapt
1279