terom@11: #include <stdlib.h>
terom@11: 
terom@11: #include <png.h>
terom@11: 
terom@11: #include "common.h"
terom@17: #include "render_struct.h"
terom@17: #include "render_png_struct.h"
terom@11: #include "render_png.h"
terom@11: 
terom@11: 
terom@13: static void _render_png_write(png_structp png_ptr, png_bytep data, png_size_t length) {
terom@11:     struct render_png *ctx = png_get_io_ptr(png_ptr);
terom@11: 
terom@13:     if (ctx->io_write_fn)
terom@13:         if (ctx->io_write_fn(data, length, ctx->cb_arg)) {
terom@11:             // error, doesn't return
terom@11:             png_error(png_ptr, "_render_png_write: io_write_fn");
terom@11:         }
terom@11: }
terom@11: 
terom@13: static void _render_png_flush(png_structp png_ptr) {
terom@11:     struct render_png *ctx = png_get_io_ptr(png_ptr);
terom@11:     
terom@13:     if (ctx->io_flush_fn)
terom@13:         if (ctx->io_flush_fn(ctx->cb_arg)) {
terom@11:             // error, doesn't return
terom@11:             png_error(png_ptr, "_render_png_flush: io_flush_fn");
terom@11:         }
terom@11: }
terom@11: 
terom@13: static void _render_png_free (struct render_png *ctx) {
terom@17:     render_png_deinit(ctx);
terom@17:     
terom@17:     if (ctx->owned_by_me)
terom@17:         free(ctx);
terom@11: }
terom@11: 
terom@19: void render_png_deinit (struct render_png *ctx) {
terom@19:     // are we initialized?
terom@19:     if (ctx->png_ptr) {
terom@19:         // libpng error handling
terom@19:         if (setjmp(png_jmpbuf(ctx->png_ptr)))
terom@19:             ERROR("libpng");
terom@19:         
terom@19:         png_destroy_write_struct(&ctx->png_ptr, &ctx->info_ptr);
terom@19:     }
terom@11: 
terom@19:     return;
terom@11: 
terom@17: error:
terom@19:     WARNING("destroying our libpng structures failed, possible memory leak?");
terom@17: }
terom@17: 
terom@17: /*
terom@17:  * Note that it's vitally important not to call any libpng functions directly,
terom@17:  * the error-handling setjmp will be invalid.
terom@17:  */
terom@17: 
terom@17: int render_png_init (struct render_png *ctx, struct render *render) {
terom@13:     // store some info from the struct render
terom@13:     ctx->io_write_fn = render->io_write_fn;
terom@13:     ctx->io_flush_fn = render->io_flush_fn;
terom@13:     ctx->cb_arg = render->cb_arg;
terom@11: 
terom@11:     // libpng initialization
terom@11:     if (!(ctx->png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL)))
terom@11:         ERROR("png_create_write_struct");
terom@11: 
terom@11:     if (!(ctx->info_ptr = png_create_info_struct(ctx->png_ptr)))
terom@11:         ERROR("png_create_info_struct");
terom@11: 
terom@11:     // libpng error handling
terom@11:     if (setjmp(png_jmpbuf(ctx->png_ptr)))
terom@11:         ERROR("libpng");
terom@11:     
terom@11:     if (render->io_stream) {
terom@11:         // use normal libpng I/O
terom@11:         // XXX: who fcloses this?
terom@11:         png_init_io(ctx->png_ptr, render->io_stream);
terom@11:     } else {
terom@11:         // setup our custom I/O callbacks
terom@11:         png_set_write_fn(ctx->png_ptr, ctx, &_render_png_write, &_render_png_flush);
terom@11:     }
terom@11: 
terom@11:     // some PNG metadata
terom@11:     png_set_IHDR(ctx->png_ptr, ctx->info_ptr, render->img_w, render->img_h, 8, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
terom@11: 
terom@11:     // write out the PNG header
terom@11:     png_write_info(ctx->png_ptr, ctx->info_ptr);
terom@17:     
terom@17:     // success
terom@17:     return 0;
terom@17: 
terom@17: error:
terom@17:     render_png_deinit(ctx);
terom@17:     return -1;
terom@17: }
terom@17: 
terom@17: struct render_png *render_png_alloc (struct render *render) {
terom@17:     struct render_png *ctx = NULL;
terom@17: 
terom@17:     // calloc the render_png
terom@17:     if (!(ctx = calloc(1, sizeof(struct render_png))))
terom@17:         ERROR("calloc");
terom@17:     
terom@17:     // I need to free it
terom@17:     ctx->owned_by_me = 1;
terom@17: 
terom@17:     // init it
terom@17:     if (render_png_init(ctx, render))
terom@17:         goto error;
terom@11: 
terom@11:     // success
terom@11:     return ctx;
terom@11: 
terom@11: error:
terom@11:     _render_png_free(ctx);
terom@11:     return NULL;
terom@11: }
terom@11: 
terom@11: int render_png_row (struct render_png *ctx, unsigned char *rowbuf) {
terom@11:     // libpng error handling
terom@11:     if (setjmp(png_jmpbuf(ctx->png_ptr)))
terom@11:         ERROR("libpng");
terom@11: 
terom@11:     // write it in
terom@11:     png_write_row(ctx->png_ptr, rowbuf);
terom@11: 
terom@11:     // success
terom@11:     return 0;
terom@11: 
terom@11: error:
terom@15:     // don't free it here, our user needs to do that
terom@11:     return -1;
terom@11: }
terom@11: 
terom@11: int render_png_done (struct render_png *ctx) {
terom@11:     // libpng error handling
terom@11:     if (setjmp(png_jmpbuf(ctx->png_ptr)))
terom@11:         ERROR("libpng");
terom@11: 
terom@11:     // write end
terom@11:     png_write_end(ctx->png_ptr, ctx->info_ptr);
terom@13:     
terom@13:     // free everything
terom@13:     _render_png_free(ctx);
terom@11: 
terom@11:     // success
terom@11:     return 0;
terom@11: 
terom@11: error:
terom@11:     _render_png_free(ctx);
terom@11:     return -1;
terom@11: }
terom@11: 
terom@11: int render_png_abort (struct render_png *ctx) {
terom@13:     // just free it
terom@11:     _render_png_free(ctx);
terom@11: 
terom@11:     // success
terom@11:     return 0;
terom@11: }
terom@11: