73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
// Known chunk types
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#define PNG_IHDR 'IHDR'
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#define PNG_IDAT 'IDAT'
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#define PNG_IEND 'IEND'
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#define PNG_tEXt 'tEXt'
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#define PNG_PLTE 'PLTE'
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#define PNG_bKGD 'bKGD'
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#define PNG_cHRM 'cHRM'
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#define PNG_gAMA 'gAMA'
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#define PNG_hIST 'hIST'
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#define PNG_iCCP 'iCCP'
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#define PNG_iTXt 'iTXt'
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#define PNG_oFFs 'oFFs'
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#define PNG_pCAL 'pCAL'
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#define PNG_sCAL 'sCAL'
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#define PNG_pHYs 'pHYs'
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#define PNG_sBIT 'sBIT'
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#define PNG_sPLT 'sPLT'
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#define PNG_sRGB 'sRGB'
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#define PNG_tIME 'tIME'
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#define PNG_tRNS 'tRNS'
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#define PNG_zTXt 'zTXt'
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// Filter values
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#define PNG_FILTER_VALUE_NONE 0
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#define PNG_FILTER_VALUE_SUB 1
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#define PNG_FILTER_VALUE_UP 2
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#define PNG_FILTER_VALUE_AVG 3
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#define PNG_FILTER_VALUE_PAETH 4
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#define PNG_FILTER_NUM 5
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// Common defines and typedefs
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#define MAX_PNG_WIDTH 4096
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#define MAX_PNG_DEPTH 4
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typedef unsigned char byte;
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typedef unsigned short word;
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typedef unsigned long ulong;
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#pragma pack(push)
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#pragma pack(1)
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typedef struct png_ihdr_s
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{
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ulong width;
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ulong height;
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byte bitdepth; // Bits per sample (not per pixel)
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byte colortype; // bit 0 - palette; bit 1 - RGB; bit 2 - alpha channel
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byte compression; // 0 for zip - error otherwise
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byte filter; // 0 for adaptive with the 5 basic types - error otherwise
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byte interlace; // 0 for no interlace - 1 for Adam7 interlace
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} png_ihdr_t;
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#pragma pack(pop)
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typedef struct png_image_s
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{
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byte *data;
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ulong width;
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ulong height;
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ulong bytedepth;
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bool isimage;
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} png_image_t;
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bool LoadPNG32 (char *name, byte **pixels, int *width, int *height, int *bytedepth);
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bool LoadPNG8 (char *name, byte **pixels, int *width, int *height);
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bool PNG_Save(const char *name, byte *data, int width, int height, int bytedepth);
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// end
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