Move JPEG saving into libqscale. Hooray, we have a usable lib!

[qscale] / libqscale.c

diff --git a/libqscale.c b/libqscale.c
index 538dd80079ce340915b47ba1cd4351b79e7020ba..168cb8ec13bf681010e0e227251fb0344eac167e 100644 (file)
--- a/libqscale.c
+++ b/libqscale.c
@@ -535,3 +535,83 @@ qscale_img *qscale_scale(qscale_img *src, unsigned width, unsigned height, unsig
 
        return dst;
 }
+
+int qscale_save_jpeg(const qscale_img *img, const char *filename, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
+{
+       FILE *file = fopen(filename, "wb");
+       if (file == NULL) {
+               return -1;
+       }
+
+       int err = qscale_save_jpeg_to_stdio(img, file, jpeg_quality, jpeg_mode);
+
+       fclose(file);
+       return err;
+}
+
+int qscale_save_jpeg_to_stdio(const qscale_img *img, FILE *file, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
+{
+        struct jpeg_compress_struct cinfo;
+        struct jpeg_error_mgr jerr;
+        cinfo.err = jpeg_std_error(&jerr);
+        jpeg_create_compress(&cinfo);
+        jpeg_stdio_dest(&cinfo, stdout);
+        cinfo.input_components = 3;
+        jpeg_set_defaults(&cinfo);
+        jpeg_set_quality(&cinfo, jpeg_quality, FALSE);
+        cinfo.image_width = img->width;
+        cinfo.image_height = img->height;
+        cinfo.raw_data_in = TRUE;
+        jpeg_set_colorspace(&cinfo, JCS_YCbCr);
+        cinfo.comp_info[0].h_samp_factor = img->samp_h0;
+        cinfo.comp_info[0].v_samp_factor = img->samp_v0;
+        cinfo.comp_info[1].h_samp_factor = img->samp_h1;
+        cinfo.comp_info[1].v_samp_factor = img->samp_v1;
+        cinfo.comp_info[2].h_samp_factor = img->samp_h2;
+        cinfo.comp_info[2].v_samp_factor = img->samp_v2;
+        jpeg_start_compress(&cinfo, TRUE);
+
+        unsigned dstride0 = (img->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
+        unsigned dstride1 = (img->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
+        unsigned dstride2 = (img->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
+
+        int total_lines = 0;
+        int blocks = 0;
+        while (total_lines < cinfo.comp_info[0].height_in_blocks * DCTSIZE) {
+                unsigned max_lines = cinfo.max_v_samp_factor * DCTSIZE;
+
+                JSAMPROW y_row_ptrs[max_lines];
+                JSAMPROW cb_row_ptrs[max_lines];
+                JSAMPROW cr_row_ptrs[max_lines];
+                JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
+                int i;
+
+                for (i = 0; i < max_lines; ++i) {
+                        /* simple edge extension */
+                        int yline = i + blocks*DCTSIZE*cinfo.comp_info[0].v_samp_factor;
+                        if (yline > img->h0 - 1)
+                                yline = img->h0 - 1;
+
+                        int cbline = i + blocks*DCTSIZE*cinfo.comp_info[1].v_samp_factor;
+                       if (cbline > img->h1 - 1)
+                                cbline = img->h1 - 1;
+
+                        int crline = i + blocks*DCTSIZE*cinfo.comp_info[2].v_samp_factor;
+                        if (crline > img->h2 - 1)
+                                crline = img->h2 - 1;
+
+                        y_row_ptrs[i]  = img->data_y  + yline * dstride0;
+                        cb_row_ptrs[i] = img->data_cb + cbline * dstride1;
+                        cr_row_ptrs[i] = img->data_cr + crline * dstride2;
+                }
+
+                total_lines += max_lines;
+                ++blocks;
+
+                jpeg_write_raw_data(&cinfo, ptrs, max_lines);
+        }
+        jpeg_finish_compress(&cinfo);
+        jpeg_destroy_compress(&cinfo);
+
+       return 0;
+}