terom@17: #ifndef RENDER_SLICES_H
terom@17: #define RENDER_SLICES_H
terom@17: 
terom@17: #include "render.h"
terom@17: 
terom@17: #define RENDER_SLICES_MAX 2
terom@17: 
terom@17: struct render_slices;
terom@17: 
terom@17: struct render_slice_info {
terom@17:     // our index
terom@17:     size_t index;
terom@17: 
terom@17:     // the render info
terom@17:     struct render *render_info;
terom@17: 
terom@17:     // where to put the pixel data
terom@17:     unsigned char *render_buf;
terom@17: };
terom@17: 
terom@17: /*
terom@17:  * Split the given render operation into multiple slices that can be rendered
terom@17:  * induvidually.
terom@17:  *
terom@17:  * A segment is a single row of a slice. The raw pixel data for each segment
terom@17:  * should be stored into the render_buf item in that slice's render_slice_info.
terom@17:  * When a full segment has been stored into the render_buf, you should call
terom@17:  * render_slices_segment_done with that slice's index as an argument, and then
terom@17:  * proceed based on its return code.
terom@17:  *
terom@17:  * Returns a struct render_slices handle which can be used to operate on the
terom@17:  * slices, or NULL on failure.
terom@17:  */
terom@17: struct render_slices *render_slices_alloc (struct render *render);
terom@17: 
terom@17: /*
terom@17:  * Get the number of slices that need to be rendered, which is also the valid
terom@17:  * range of index values for render_slices_get_slice_info.
terom@17:  */
terom@17: int render_slices_get_count (struct render_slices *ctx);
terom@17: 
terom@17: /*
terom@17:  * Get the struct render_slice_info corresponding to the given index. This
terom@17:  * the information required to render the segment. The index is used as an
terom@17:  * argument to render_slices_segment_done.
terom@17:  */
terom@17: struct render_slice_info *render_slices_get_slice_info (struct render_slices *ctx, int index);
terom@17: 
terom@17: /*
terom@17:  * You may call render_slices_segment_done again for any slice now, including
terom@17:  * those which returned ~SLICE_CONTINUE earlier.
terom@17:  */
terom@17: #define SLICE_CONTINUE 0x01
terom@17: 
terom@17: /*
terom@17:  * You may call render_slices_process_row next.
terom@17:  */
terom@17: #define SLICE_PROCESS_ROW 0x02
terom@17: 
terom@19: // XXX: you can't modify the slice's row buffer until these return SLICE_CONTINUE
terom@19: 
terom@17: /*
terom@17:  * The render_buf for the render_slice_info with the given index value contains
terom@17:  * the full information for the next row of the render_info render. Returns a
terom@18:  * bitwise-OR of the SLICE_* flags, or -1 for an error:
terom@17:  *
terom@17:  * Valid return values:
terom@17:  *  zero
terom@17:  *      Do not call segment_done for this index, or process_row right now.
terom@17:  *      Information for some slice needed to complete the next row is missing,
terom@17:  *      and the other segments must call segment_done first.
terom@17:  * 
terom@17:  *  SLICE_PROCESS_ROW
terom@17:  *      Do not call segment_done for this index or any others, but do call
terom@17:  *      process_row as soon as possible, and then continue once it returns
terom@17:  *      (see render_slices_process_row).
terom@17:  *  
terom@17:  *  SLICE_CONTINUE & SLICE_PROCESS_ROW
terom@17:  *      You should call process_row next, but you can also call segment_done
terom@17:  *      for all segments that returned ~SLICE_CONTINUE earlier.
terom@17:  *
terom@17:  * -1   - An error occured. Rendering must be aborted.
terom@17:  *
terom@17:  */
terom@17: int render_slices_segment_done (struct render_slices *ctx, int index);
terom@17: 
terom@17: /*
terom@17:  * Process a completed row and generate output in the PNG format (how that is
terom@17:  * handled depends on the render given to render_slices_alloc/init). Returns a
terom@18:  * bitwise-OR of the SLICE_* flags, or -1 for an error:
terom@17:  *
terom@17:  * Valid return values :
terom@17:  *  zero
terom@17:  *      The PNG is done - you don't need to call segment_done or process_row
terom@17:  *      anymore, doing so will result in an error. You don't need to deinit
terom@17:  *      ctx, but you may need to free it.
terom@17:  *
terom@17:  *  SLICE_CONTINUE
terom@17:  *      You may call render_slices_segment_done again for those slices that
terom@17:  *      returned ~SLICE_CONTINUE earlier.
terom@17:  *
terom@17:  *  SLICE_CONTINUE & SLICE_PROCESS_ROW
terom@17:  *      In addition to calling render_slices_segment_done again, you may also
terom@17:  *      call render_slices_process_row again.
terom@17:  *
terom@17:  * -1   - An error occured. Rendering must be aborted.
terom@17:  */
terom@17: int render_slices_process_row (struct render_slices *ctx);
terom@17: 
terom@17: /*
terom@18:  * Signifiy that the render has been completed. This will flush out buffered
terom@18:  * output data.
terom@18:  */
terom@18: int render_slices_done (struct render_slices *ctx);
terom@18: 
terom@18: /*
terom@17:  * Free a render_slices. The rendering may or may not be complete.
terom@17:  */
terom@17: void render_slices_free (struct render_slices *ctx);
terom@17: 
terom@17: #endif /* RENDER_SLICES_H */