X-Git-Url: https://git.sesse.net/?p=qscale;a=blobdiff_plain;f=libqscale.c;fp=libqscale.c;h=b744a9b5f3b98e1a1da8182e15f9eaefc991f694;hp=0000000000000000000000000000000000000000;hb=cce321fe623a347fd2bda4e442bed42dfc9299c7;hpb=9d3e18175a68b3ffe71bb1a68c7fba0f9624d5f1

diff --git a/libqscale.c b/libqscale.c
new file mode 100644
index 0000000..b744a9b
--- /dev/null
+++ b/libqscale.c
@@ -0,0 +1,100 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <malloc.h>
+
+#include "libqscale.h"
+
+qscale_img *qscale_load_jpeg(const char *filename)
+{
+	FILE *file = fopen(filename, "rb");
+	qscale_img *img;
+	if (file == NULL) {
+		return NULL;
+	}
+
+	img = qscale_load_jpeg_from_stdio(file);
+
+	fclose(file);
+	return img;
+}
+
+qscale_img *qscale_load_jpeg_from_stdio(FILE *file)
+{
+	qscale_img *img = (qscale_img *)malloc(sizeof(qscale_img));
+	if (img == NULL) {
+		return NULL;
+	}
+
+	img->data_y = img->data_cb = img->data_cr = NULL;
+
+	/* FIXME: Better error handling here (ie., return NULL). */
+	struct jpeg_decompress_struct dinfo;
+	struct jpeg_error_mgr jerr;
+	dinfo.err = jpeg_std_error(&jerr);
+	jpeg_create_decompress(&dinfo);
+	jpeg_stdio_src(&dinfo, stdin);
+	jpeg_read_header(&dinfo, TRUE);
+	dinfo.raw_data_out = TRUE;
+	jpeg_start_decompress(&dinfo);
+	
+	/* We do not handle anything but YCbCr images (yet?). */
+	if (dinfo.num_components != 3) {
+		qscale_destroy(img);
+		return NULL;
+	}
+
+	img->width = dinfo.image_width;
+	img->height = dinfo.image_height;
+
+	img->w0 = dinfo.image_width * dinfo.comp_info[0].h_samp_factor / dinfo.max_h_samp_factor;
+	img->h0 = dinfo.image_height * dinfo.comp_info[0].v_samp_factor / dinfo.max_v_samp_factor;
+
+	img->w1 = dinfo.image_width * dinfo.comp_info[1].h_samp_factor / dinfo.max_h_samp_factor;
+	img->h1 = dinfo.image_height * dinfo.comp_info[1].v_samp_factor / dinfo.max_v_samp_factor;
+
+	img->w2 = dinfo.image_width * dinfo.comp_info[2].h_samp_factor / dinfo.max_h_samp_factor;
+	img->h2 = dinfo.image_height * dinfo.comp_info[2].v_samp_factor / dinfo.max_v_samp_factor;
+
+	img->data_y  = (JSAMPLE*)memalign(16, dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
+	img->data_cb = (JSAMPLE*)memalign(16, dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
+	img->data_cr = (JSAMPLE*)memalign(16, dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
+
+	if (img->data_y == NULL || img->data_cb == NULL || img->data_cr == NULL) {
+		qscale_destroy(img);
+		return NULL;
+	}
+
+	int total_lines = 0, blocks = 0;
+        while (total_lines < dinfo.comp_info[0].height_in_blocks * DCTSIZE) {
+                unsigned max_lines = dinfo.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) {
+                        y_row_ptrs[i]  = img->data_y  + (i+blocks*DCTSIZE*dinfo.comp_info[0].v_samp_factor) * dinfo.comp_info[0].width_in_blocks * DCTSIZE;
+                        cb_row_ptrs[i] = img->data_cb + (i+blocks*DCTSIZE*dinfo.comp_info[1].v_samp_factor) * dinfo.comp_info[1].width_in_blocks * DCTSIZE;
+                        cr_row_ptrs[i] = img->data_cr + (i+blocks*DCTSIZE*dinfo.comp_info[2].v_samp_factor) * dinfo.comp_info[2].width_in_blocks * DCTSIZE;
+                }
+
+                total_lines += max_lines;
+                ++blocks;
+
+                if (jpeg_read_raw_data(&dinfo, ptrs, max_lines) == 0)
+                        break;
+        }
+
+	jpeg_destroy_decompress(&dinfo);
+	return img;
+}
+
+void qscale_destroy(qscale_img *img)
+{
+	free(img->data_y);
+	free(img->data_cb);
+	free(img->data_cr);
+	free(img);
+}