1 #ifndef PNGTILE_PNG_H

     2 #define PNGTILE_PNG_H

     3 

     4 /**

     5  * @file

     6  * PNG-specific handling

     7  */

     8 #include <png.h>

     9 #include <stdint.h>

    10 

    11 /**

    12  * Handle sparse data at this granularity (pixels)

    13  */

    14 #define PT_IMG_BLOCK_SIZE 64

    15 

    16 /**

    17  * PNG img state

    18  */

    19 struct pt_png_img {

    20     /** libpng state */

    21     png_struct *png;

    22     png_info *info;

    23 

    24 };

    25 

    26 /**

    27  * Cache header layout for PNG-format images

    28  */

    29 struct pt_png_header {

    30     /** Pixel dimensions of image */

    31     uint32_t width, height;

    32     

    33     /** Pixel format */

    34     uint8_t bit_depth, color_type;

    35 

    36     /** Number of png_color entries that follow */

    37     uint16_t num_palette;

    38 

    39     /** Number of bytes per row */

    40     uint32_t row_bytes;

    41     

    42     /** Number of bytes per pixel */

    43     uint8_t col_bytes;

    44 

    45     /** Palette entries, up to 256 entries used */

    46     png_color palette[PNG_MAX_PALETTE_LENGTH];

    47 };

    48 

    49 

    50 #include "image.h"

    51 #include "tile.h"

    52 

    53 

    54 /**

    55  * Open the given .png image, and read info

    56  */

    57 int pt_png_open (struct pt_image *image, struct pt_png_img *img);

    58 

    59 /**

    60  * Fill in the PNG header and return the size of the pixel data

    61  */

    62 int pt_png_read_header (struct pt_png_img *img, struct pt_png_header *header, size_t *data_size);

    63 

    64 /**

    65  * Decode the PNG data into the given data segment, using the header as decoded by pt_png_read_header

    66  */

    67 int pt_png_decode (struct pt_png_img *img, const struct pt_png_header *header, const struct pt_image_params *params, uint8_t *out);

    68 

    69 /**

    70  * Fill in img_* fields of pt_image_info from header

    71  */

    72 int pt_png_info (struct pt_png_header *header, struct pt_image_info *info);

    73 

    74 /**

    75  * Render out a tile

    76  */

    77 int pt_png_tile (struct pt_png_header *header, uint8_t *data, struct pt_tile *tile);

    78 

    79 /**

    80  * Release pt_png_ctx resources as allocated by pt_png_open

    81  */

    82 void pt_png_release_read (struct pt_png_img *img);

    83 

    84 /**

    85  * Release pt_png_ctx resources as allocated by pt_png_...

    86  */

    87 void pt_png_release_write (struct pt_png_img *img);

    88 

    89 #endif