172 lines
7.4 KiB
C
172 lines
7.4 KiB
C
/********************************************************************************************
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PNGU Version : 0.2a
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Coder : frontier
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More info : http://frontier-dev.net
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********************************************************************************************/
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#ifndef __PNGU__
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#define __PNGU__
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// Return codes
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#define PNGU_OK 0
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#define PNGU_ODD_WIDTH 1
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#define PNGU_ODD_STRIDE 2
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#define PNGU_INVALID_WIDTH_OR_HEIGHT 3
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#define PNGU_FILE_IS_NOT_PNG 4
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#define PNGU_UNSUPPORTED_COLOR_TYPE 5
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#define PNGU_NO_FILE_SELECTED 6
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#define PNGU_CANT_OPEN_FILE 7
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#define PNGU_CANT_READ_FILE 8
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#define PNGU_LIB_ERROR 9
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// Color types
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#define PNGU_COLOR_TYPE_GRAY 1
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#define PNGU_COLOR_TYPE_GRAY_ALPHA 2
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#define PNGU_COLOR_TYPE_PALETTE 3
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#define PNGU_COLOR_TYPE_RGB 4
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#define PNGU_COLOR_TYPE_RGB_ALPHA 5
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#define PNGU_COLOR_TYPE_UNKNOWN 6
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#ifdef __cplusplus
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extern "C" {
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#endif
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// Types
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typedef unsigned char PNGU_u8;
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typedef unsigned short PNGU_u16;
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typedef unsigned int PNGU_u32;
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typedef unsigned long long PNGU_u64;
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typedef struct
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{
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PNGU_u8 r;
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PNGU_u8 g;
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PNGU_u8 b;
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} PNGUCOLOR;
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typedef struct
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{
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PNGU_u32 imgWidth; // In pixels
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PNGU_u32 imgHeight; // In pixels
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PNGU_u32 imgBitDepth; // In bitx
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PNGU_u32 imgColorType; // PNGU_COLOR_TYPE_*
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PNGU_u32 validBckgrnd; // Non zero if there is a background color
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PNGUCOLOR bckgrnd; // Backgroun color
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PNGU_u32 numTrans; // Number of transparent colors
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PNGUCOLOR *trans; // Transparent colors
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} PNGUPROP;
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// Image context, always initialize with SelectImageFrom* and free with ReleaseImageContext
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struct _IMGCTX;
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typedef struct _IMGCTX *IMGCTX;
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/****************************************************************************
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* Pixel conversion *
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****************************************************************************/
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// Macro to convert RGB8 values to RGB565
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#define PNGU_RGB8_TO_RGB565(r,g,b) ( ((((PNGU_u16) r) & 0xF8U) << 8) | ((((PNGU_u16) g) & 0xFCU) << 3) | (((PNGU_u16) b) >> 3) )
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// Macro to convert RGBA8 values to RGB5A3
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#define PNGU_RGB8_TO_RGB5A3(r,g,b,a) (PNGU_u16) (((a & 0xE0U) == 0xE0U) ? \
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(0x8000U | ((((PNGU_u16) r) & 0xF8U) << 7) | ((((PNGU_u16) g) & 0xF8U) << 2) | (((PNGU_u16) b) >> 3)) : \
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(((((PNGU_u16) a) & 0xE0U) << 7) | ((((PNGU_u16) r) & 0xF0U) << 4) | (((PNGU_u16) g) & 0xF0U) | ((((PNGU_u16) b) & 0xF0U) >> 4)))
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// Function to convert two RGB8 values to YCbYCr
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PNGU_u32 PNGU_RGB8_TO_YCbYCr (PNGU_u8 r1, PNGU_u8 g1, PNGU_u8 b1, PNGU_u8 r2, PNGU_u8 g2, PNGU_u8 b2);
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// Function to convert an YCbYCr to two RGB8 values.
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void PNGU_YCbYCr_TO_RGB8 (PNGU_u32 ycbycr, PNGU_u8 *r1, PNGU_u8 *g1, PNGU_u8 *b1, PNGU_u8 *r2, PNGU_u8 *g2, PNGU_u8 *b2);
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/****************************************************************************
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* Image context handling *
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****************************************************************************/
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// Selects a PNG file, previosly loaded into a buffer, and creates an image context for subsequent procesing.
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IMGCTX PNGU_SelectImageFromBuffer (const void *buffer);
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// Selects a PNG file, from any devoptab device, and creates an image context for subsequent procesing.
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IMGCTX PNGU_SelectImageFromDevice (const char *filename);
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// Frees resources associated with an image context. Always call this function when you no longer need the IMGCTX.
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void PNGU_ReleaseImageContext (IMGCTX ctx);
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/****************************************************************************
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* Miscelaneous *
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****************************************************************************/
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// Retrieves info from selected PNG file, including image dimensions, color format, background and transparency colors.
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int PNGU_GetImageProperties (IMGCTX ctx, PNGUPROP *fileproperties);
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/****************************************************************************
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* Image conversion *
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****************************************************************************/
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// Expands selected image into an YCbYCr buffer. You need to specify context, image dimensions,
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// destination address and stride in pixels (stride = buffer width - image width).
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int PNGU_DecodeToYCbYCr (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride);
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// Macro for decoding an image inside a buffer at given coordinates.
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#define PNGU_DECODE_TO_COORDS_YCbYCr(ctx,coordX,coordY,imgWidth,imgHeight,bufferWidth,bufferHeight,buffer) \
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\
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PNGU_DecodeToYCbYCr (ctx, imgWidth, imgHeight, ((void *) buffer) + (coordY) * (bufferWidth) * 2 + \
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(coordX) * 2, (bufferWidth) - (imgWidth))
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// Expands selected image into a linear RGB565 buffer. You need to specify context, image dimensions,
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// destination address and stride in pixels (stride = buffer width - image width).
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int PNGU_DecodeToRGB565 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride);
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// Macro for decoding an image inside a buffer at given coordinates.
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#define PNGU_DECODE_TO_COORDS_RGB565(ctx,coordX,coordY,imgWidth,imgHeight,bufferWidth,bufferHeight,buffer) \
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\
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PNGU_DecodeToRGB565 (ctx, imgWidth, imgHeight, ((void *) buffer) + (coordY) * (bufferWidth) * 2 + \
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(coordX) * 2, (bufferWidth) - (imgWidth))
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// Expands selected image into a linear RGBA8 buffer. You need to specify context, image dimensions,
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// destination address, stride in pixels and default alpha value, which is used if the source image
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// doesn't have an alpha channel.
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int PNGU_DecodeToRGBA8 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride, PNGU_u8 default_alpha);
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// Macro for decoding an image inside a buffer at given coordinates.
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#define PNGU_DECODE_TO_COORDS_RGBA8(ctx,coordX,coordY,imgWidth,imgHeight,default_alpha,bufferWidth,bufferHeight,buffer) \
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\
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PNGU_DecodeToRGBA8 (ctx, imgWidth, imgHeight, ((void *) buffer) + (coordY) * (bufferWidth) * 2 + \
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(coordX) * 2, (bufferWidth) - (imgWidth), default_alpha)
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// Expands selected image into a 4x4 tiled RGB565 buffer. You need to specify context, image dimensions
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// and destination address.
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int PNGU_DecodeTo4x4RGB565 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer);
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// Expands selected image into a 4x4 tiled RGB5A3 buffer. You need to specify context, image dimensions,
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// destination address and default alpha value, which is used if the source image doesn't have an alpha channel.
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int PNGU_DecodeTo4x4RGB5A3 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u8 default_alpha);
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// Expands selected image into a 4x4 tiled RGBA8 buffer. You need to specify context, image dimensions,
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// destination address and default alpha value, which is used if the source image doesn't have an alpha channel.
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int PNGU_DecodeTo4x4RGBA8 (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u8 default_alpha);
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// Encodes an YCbYCr image in PNG format and stores it in the selected device or memory buffer. You need to
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// specify context, image dimensions, destination address and stride in pixels (stride = buffer width - image width).
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int PNGU_EncodeFromYCbYCr (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, void *buffer, PNGU_u32 stride);
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// Macro for encoding an image stored into an YCbYCr buffer at given coordinates.
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#define PNGU_ENCODE_TO_COORDS_YCbYCr(ctx,coordX,coordY,imgWidth,imgHeight,bufferWidth,bufferHeight,buffer) \
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\
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PNGU_EncodeFromYCbYCr (ctx, imgWidth, imgHeight, ((void *) buffer) + (coordY) * (bufferWidth) * 2 + \
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(coordX) * 2, (bufferWidth) - (imgWidth))
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#ifdef __cplusplus
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}
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#endif
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#endif
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