Image rendering

1 files changed, 368 insertions, 0 deletions

diff --git a/libstorycode/imagestore.c b/libstorycode/imagestore.c
new file mode 100644
index 0000000..5eb50fb
--- /dev/null
+++ b/libstorycode/imagestore.c
@@ -0,0 +1,368 @@
+/*
+ * imagestore.c
+ *
+ * Copyright © 2013-2018 Thomas White <taw@bitwiz.org.uk>
+ *
+ * This file is part of Colloquium.
+ *
+ * Colloquium is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <libgen.h>
+#include <cairo.h>
+#include <glib.h>
+#include <gio/gio.h>
+#include <gdk/gdk.h>
+#include <gdk-pixbuf/gdk-pixbuf.h>
+
+#include "imagestore.h"
+
+#define MAX_SIZES (32)
+
+struct image_record
+{
+	char *filename;
+	cairo_surface_t *surf[MAX_SIZES];
+	int w[MAX_SIZES];
+	int last_used[MAX_SIZES];
+	int n_sizes;
+	int h_last_used;
+	int full_width;
+	int full_height;
+};
+
+
+struct _imagestore
+{
+	int n_images;
+	struct image_record *images;
+	int max_images;
+	GFile *pparent;
+	GFile *iparent;
+	const char *storename;
+};
+
+
+static int alloc_images(ImageStore *is, int new_max_images)
+{
+	struct image_record *images_new;
+
+	images_new = realloc(is->images,
+	                     sizeof(struct image_record)*new_max_images);
+	if ( images_new == NULL ) return 1;
+
+	is->images = images_new;
+	is->max_images = new_max_images;
+	return 0;
+}
+
+
+ImageStore *imagestore_new(const char *storename)
+{
+	ImageStore *is;
+
+	is = calloc(1, sizeof(ImageStore));
+	if ( is == NULL ) return NULL;
+
+	is->images = NULL;
+	is->pparent = NULL;
+	if ( storename != NULL ) {
+		is->iparent = g_file_new_for_uri(storename);
+	} else {
+		is->iparent = NULL;
+	}
+	is->n_images = 0;
+	is->max_images = 0;
+	if ( alloc_images(is, 32) ) {
+		free(is);
+		return NULL;
+	}
+
+	return is;
+}
+
+
+void imagestore_set_parent(ImageStore *is, GFile *parent)
+{
+	if ( is->pparent != NULL ) {
+		g_object_unref(is->pparent);
+	}
+	is->pparent = parent;
+}
+
+
+void imagestore_destroy(ImageStore *is)
+{
+	int i;
+
+	for ( i=0; i<is->n_images; i++ ) {
+		int j;
+		free(is->images[i].filename);
+		for ( j=0; j<is->images[i].n_sizes; j++ ) {
+			if ( is->images[i].surf[j] != NULL ) {
+				g_object_unref(is->images[i].surf[j]);
+			}
+		}
+	}
+	g_object_unref(is->pparent);
+	g_object_unref(is->iparent);
+	free(is->images);
+	free(is);
+}
+
+
+static cairo_surface_t *pixbuf_to_surface(GdkPixbuf *t)
+{
+	cairo_surface_t *surf;
+	cairo_t *cr;
+	int w, h;
+
+	if ( t == NULL ) return NULL;
+
+	w = gdk_pixbuf_get_width(t);
+	h = gdk_pixbuf_get_height(t);
+
+	surf = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, w, h);
+	if ( surf == NULL ) return NULL;
+
+	cr = cairo_create(surf);
+
+	gdk_cairo_set_source_pixbuf(cr, t, 0, 0);
+	cairo_pattern_t *patt = cairo_get_source(cr);
+	cairo_pattern_set_extend(patt, CAIRO_EXTEND_PAD);
+	cairo_pattern_set_filter(patt, CAIRO_FILTER_BEST);
+	cairo_paint(cr);
+
+	cairo_destroy(cr);
+
+	return surf;
+}
+
+
+static int try_load(GFile *file, GdkPixbuf **pixbuf, gint w, gint h)
+{
+	GFileInputStream *stream;
+	GError *error = NULL;
+
+	stream = g_file_read(file, NULL, &error);
+	if ( stream != NULL ) {
+		GError *pberr = NULL;
+		*pixbuf = gdk_pixbuf_new_from_stream_at_scale(G_INPUT_STREAM(stream),
+		                                              w, h, TRUE,
+		                                              NULL, &pberr);
+		g_object_unref(stream);
+		g_object_unref(file);
+		return 1;
+	}
+
+	return 0;
+}
+
+
+static GdkPixbuf *load_image(const char *uri, GFile *pparent, GFile *iparent,
+                             gint w, gint h)
+{
+	GFile *file;
+	GdkPixbuf *pixbuf;
+
+	/* Literal pathname */
+	file = g_file_new_for_path(uri);
+	if ( try_load(file, &pixbuf, w, h) ) return pixbuf;
+
+	/* Try the file prefixed with the directory the presentation is in */
+	if ( pparent != NULL ) {
+		file = g_file_get_child(pparent, uri);
+		if ( try_load(file, &pixbuf, w, h) ) return pixbuf;
+	}
+
+	/* Try prefixing with imagestore folder */
+	if ( iparent != NULL ) {
+		file = g_file_get_child(iparent, uri);
+		if ( try_load(file, &pixbuf, w, h) ) return pixbuf;
+	}
+
+	return NULL;
+}
+
+
+static struct image_record *add_image_record(ImageStore *is,
+                                             const char *filename)
+{
+	int idx;
+
+	if ( is->n_images == is->max_images ) {
+		if ( alloc_images(is, is->max_images+32) ) {
+			fprintf(stderr, "Couldn't allocate memory for image "
+			        "records.\n");
+			return NULL;
+		}
+	}
+
+	idx = is->n_images++;
+
+	is->images[idx].n_sizes = 0;
+	is->images[idx].filename = strdup(filename);
+	is->images[idx].h_last_used = 0;
+
+	return &is->images[idx];
+}
+
+
+
+int imagestore_get_size(ImageStore *is, const char *filename,
+                        int *w, int *h)
+{
+	GdkPixbuf *pixbuf;
+	struct image_record *ir;
+	int i;
+
+	for ( i=0; i<is->n_images; i++ ) {
+		if ( strcmp(is->images[i].filename, filename) == 0 ) {
+			*w = is->images[i].full_width;
+			*h = is->images[i].full_height;
+			return 0;
+		}
+	}
+
+	pixbuf = load_image(filename, is->pparent, is->iparent, -1, -1);
+	if ( pixbuf == NULL ) return 1;
+
+
+	*w = gdk_pixbuf_get_width(pixbuf);
+	*h = gdk_pixbuf_get_height(pixbuf);
+
+	ir = add_image_record(is, filename);
+	if ( ir != NULL ) {
+		ir->full_width = *w;
+		ir->full_height = *h;
+	} /* otherwise can't cache, too bad */
+
+	g_object_unref(pixbuf);
+
+	return 0;
+}
+
+
+static int find_earliest(struct image_record *im)
+{
+	int i, earliest, l;
+
+	earliest = im->h_last_used;
+	l = im->n_sizes;
+
+	for ( i=0; i<im->n_sizes; i++ ) {
+		if ( im->last_used[i] < earliest ) {
+			earliest = im->last_used[i];
+			l = i;
+		}
+	}
+
+	assert(l != im->n_sizes);
+
+	cairo_surface_destroy(im->surf[l]);
+
+	return l;
+}
+
+
+static cairo_surface_t *add_image_size(struct image_record *im,
+                                       const char *filename,
+                                       GFile *pparent, GFile *iparent,
+                                       int w)
+{
+	cairo_surface_t *surf;
+	GdkPixbuf *t;
+	int pos;
+
+	t = load_image(filename, pparent, iparent, w, -1);
+	if ( t == NULL ) return NULL;
+	surf = pixbuf_to_surface(t);
+	g_object_unref(t);
+
+	/* Add surface to list */
+	if ( im->n_sizes == MAX_SIZES ) {
+		pos = find_earliest(im);
+	} else {
+		pos = im->n_sizes++;
+	}
+
+	im->w[pos] = w;
+	im->surf[pos] = surf;
+	im->last_used[pos] = im->h_last_used++;
+
+	return surf;
+}
+
+
+static cairo_surface_t *add_new_image(ImageStore *is, const char *filename, int w)
+{
+	struct image_record *ir;
+	ir = add_image_record(is, filename);
+	if ( ir == NULL ) return NULL;
+	return add_image_size(ir, filename, is->pparent, is->iparent, w);
+}
+
+
+void show_imagestore(ImageStore *is)
+{
+	int i;
+
+	printf("Store %p contains %i records.\n", is, is->n_images);
+
+	for ( i=0; i<is->n_images; i++ ) {
+
+		printf("%s :\n", is->images[i].filename);
+		printf("\n");
+
+	}
+}
+
+
+cairo_surface_t *lookup_image(ImageStore *is, const char *filename, int w)
+{
+	int i, j;
+	int found = 0;
+	cairo_surface_t *surf;
+
+	for ( i=0; i<is->n_images; i++ ) {
+		if ( strcmp(is->images[i].filename, filename) == 0 ) {
+			found = 1;
+			break;
+		}
+	}
+	if ( !found ) {
+		return add_new_image(is, filename, w);
+	}
+
+	for ( j=0; j<is->images[i].n_sizes; j++ ) {
+		if ( is->images[i].w[j] == w ) {
+			is->images[i].last_used[j] = is->images[i].h_last_used++;
+			return is->images[i].surf[j];
+		}
+	}
+
+	/* We don't have this size yet */
+	surf = add_image_size(&is->images[i], filename, is->pparent,
+	                      is->iparent, w);
+	return surf;
+}