\u8fd9\u662f\u4ece\u7f51\u4e0a\u627e\u7684\u4ee3\u7801\uff0c\u4f46\u6709\u4ee5\u4e0b\u4e24\u4e2a\u7f3a\u9677\uff1a<\/p>\n
1\u3001\u4e0d\u652f\u6301\u4ece\u5185\u5b58\u4e2d\u89e3\u6790png\u56fe\u7247\u3002<\/p>\n
2\u3001\u751f\u6210\u7684\u56fe\u7247\u6570\u636e\u4e2d\u4e0d\u5305\u542balpha\u6570\u636e\uff0c\u65e2\u4f7fpng\u56fe\u4e2d\u5e26\u6709alpha\u6570\u636e\u3002<\/p>\n
\u7ee7\u7eed\u67e5\u627ecximage\u79fb\u690dndk.<\/p>\n
unsigned char* readpng(const char* file, png_uint_32* w, png_uint_32* h,
\nbool* hasAlpha) {
\nLOGI(“readPng 1”);
\nFILE* f;
\nunsigned char sig[8];
\npng_structp png_ptr;
\npng_infop info_ptr;
\nunsigned char* image_data;
\nint bit_depth;
\nint color_type;
\nunsigned int rowbytes;
\npng_uint_32 i;
\npng_bytepp row_pointers;
\nLOGI(“readPng 2”);
\nif ((f = fopen(file, “rb”)) == NULL)
\nreturn NULL;
\nfread(sig, sizeof(*sig), sizeof(sig), f);
\n\/\/\u00a0\u00a0\u00a0 if (!png_check_sig(sig, sizeof(*sig))) {
\n\/\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 fclose(f);
\n\/\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return NULL;
\n\/\/\u00a0\u00a0\u00a0 }
\nLOGI(“readPng 3”);
\nif ((png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL,
\nNULL)) == NULL) {
\nfclose(f);
\nreturn NULL;
\n}
\nif ((info_ptr = png_create_info_struct(png_ptr)) == NULL) {
\npng_destroy_read_struct(&png_ptr, NULL, NULL);
\nfclose(f);
\nreturn NULL;
\n}
\nLOGI(“readPng 4”);
\nif (setjmp(png_jmpbuf(png_ptr))) {
\npng_destroy_read_struct(&png_ptr, &info_ptr, NULL);
\nfclose(f);
\nreturn NULL;
\n}
\nLOGI(“readPng 4.1”);
\n\/\/\u00a0\u00a0\u00a0 png_ptr->io_ptr = (png_voidp) f;
\npng_init_io(png_ptr, f); \/\/ fuck,\u52a0\u4e0a\u8fd9\u4e00\u53e5\u5c31OK\u4e86
\npng_set_sig_bytes(png_ptr, 8);
\nLOGI(“readPng 4.2”);
\npng_read_info(png_ptr, info_ptr);
\nLOGI(“readPng 4.3”);
\npng_get_IHDR(png_ptr, info_ptr, w, h, &bit_depth, &color_type, NULL, NULL,
\nNULL);
\nLOGI(“readPng 5”);
\nif (color_type & PNG_COLOR_MASK_ALPHA) {
\npng_set_strip_alpha(png_ptr);
\n*hasAlpha = true;
\n}
\nif (bit_depth == 16)
\npng_set_strip_16(png_ptr);
\nif (color_type == PNG_COLOR_TYPE_GRAY || color_type
\n== PNG_COLOR_TYPE_GRAY_ALPHA)
\npng_set_gray_to_rgb(png_ptr);
\nif (color_type == PNG_COLOR_TYPE_PALETTE)
\npng_set_palette_to_rgb(png_ptr);
\npng_read_update_info(png_ptr, info_ptr);<\/p>\n
LOGI(“readPng 6”);
\nrowbytes = png_get_rowbytes(png_ptr, info_ptr);
\nif ((image_data = (unsigned char *) malloc(*h * rowbytes)) == NULL) {
\npng_destroy_read_struct(&png_ptr, &info_ptr, NULL);
\nfclose(f);
\nreturn NULL;
\n}
\nif ((row_pointers = (png_bytepp) malloc(*h * sizeof(png_bytep))) == NULL) {
\npng_destroy_read_struct(&png_ptr, &info_ptr, NULL);
\nfclose(f);
\nfree(image_data);
\nreturn NULL;
\n}<\/p>\n
for (i = 0; i < *h; i++)
\nrow_pointers[*h – 1 – i] = image_data + i * rowbytes;
\npng_read_image(png_ptr, row_pointers);
\nfree(row_pointers);
\npng_destroy_read_struct(&png_ptr, &info_ptr, NULL);
\nfclose(f);<\/p>\n
\/\/\u00a0\u00a0 \u00a0FILE* f2=fopen(“\/sdcard\/2.png”, “w”);
\n\/\/\u00a0\u00a0 \u00a0fwrite(image_data,*h * rowbytes,1,f2);
\n\/\/\u00a0\u00a0 \u00a0fclose(f2);
\nreturn image_data;
\n}<\/p>\n","protected":false},"excerpt":{"rendered":"
\u8fd9\u662f\u4ece\u7f51\u4e0a\u627e\u7684\u4ee3\u7801\uff0c\u4f46\u6709\u4ee5\u4e0b\u4e24\u4e2a\u7f3a\u9677\uff1a 1\u3001\u4e0d\u652f\u6301\u4ece\u5185\u5b58\u4e2d\u89e3\u6790png\u56fe\u7247\u3002 2\u3001 …<\/p>\n