From 269fb9bca7bef679935001e30dcf60031253bbf9 Mon Sep 17 00:00:00 2001
From: Harry Jeffery <harry@exec64.co.uk>
Date: Mon, 21 Jan 2019 00:34:01 +0000
Subject: Add rsvg backend

---
 Makefile           |   6 ++-
 src/backend_rsvg.c | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend_rsvg.h |   9 ++++
 src/main.c         |   2 +
 4 files changed, 157 insertions(+), 1 deletion(-)
 create mode 100644 src/backend_rsvg.c
 create mode 100644 src/backend_rsvg.h

diff --git a/Makefile b/Makefile
index 6a05aa8..ca41af0 100644
--- a/Makefile
+++ b/Makefile
@@ -8,8 +8,12 @@ CONFIGPREFIX ?= /etc
 
 CFLAGS ?= -W -Wall -pedantic -Wmissing-prototypes
 CFLAGS += -std=c99
+CFLAGS += $(shell pkg-config --cflags librsvg-2.0)
 CPPFLAGS += $(shell sdl2-config --cflags) -D_XOPEN_SOURCE=700
-LIBS := $(shell sdl2-config --libs) -lfreeimage -lpng -lSDL2_ttf -lfontconfig -lpthread
+LIBS := $(shell sdl2-config --libs)
+LIBS += -lfreeimage -lpng
+LIBS += $(shell pkg-config --libs librsvg-2.0)
+LIBS += -lSDL2_ttf -lfontconfig -lpthread
 
 BUILDDIR ?= build
 TARGET := $(BUILDDIR)/imv
diff --git a/src/backend_rsvg.c b/src/backend_rsvg.c
new file mode 100644
index 0000000..f259e5c
--- /dev/null
+++ b/src/backend_rsvg.c
@@ -0,0 +1,141 @@
+#include "backend_rsvg.h"
+#include "backend.h"
+#include "source.h"
+
+#include <librsvg/rsvg.h>
+
+/* Some systems like GNU/Hurd don't define PATH_MAX */
+#ifndef PATH_MAX
+#define PATH_MAX 4096
+#endif
+
+static void source_free(struct imv_source *src)
+{
+  free(src->name);
+  src->name = NULL;
+
+  free(src);
+}
+
+static struct imv_bitmap *to_imv_bitmap(GdkPixbuf *bitmap)
+{
+  struct imv_bitmap *bmp = malloc(sizeof(struct imv_bitmap));
+  bmp->width = gdk_pixbuf_get_width(bitmap);
+  bmp->height = gdk_pixbuf_get_height(bitmap);
+  bmp->format = IMV_ARGB;
+  size_t len = bmp->width * bmp->height * 4;
+  bmp->data = malloc(len);
+  memcpy(bmp->data, gdk_pixbuf_get_pixels(bitmap), len);
+  return bmp;
+}
+
+static void report_error(struct imv_source *src)
+{
+  if (!src->callback) {
+    fprintf(stderr, "imv_source(%s) has no callback configured. "
+                    "Discarding error.\n", src->name);
+    return;
+  }
+
+  struct imv_source_message msg;
+  msg.source = src;
+  msg.user_data = src->user_data;
+  msg.bitmap = NULL;
+  msg.error = "Internal error";
+
+  src->callback(&msg);
+}
+
+
+static void send_bitmap(struct imv_source *src, GdkPixbuf *bitmap)
+{
+  if (!src->callback) {
+    fprintf(stderr, "imv_source(%s) has no callback configured. "
+                    "Discarding result.\n", src->name);
+    return;
+  }
+
+  struct imv_source_message msg;
+  msg.source = src;
+  msg.user_data = src->user_data;
+  msg.bitmap = to_imv_bitmap(bitmap);
+  msg.frametime = 0;
+  msg.error = NULL;
+
+  src->callback(&msg);
+}
+
+static void load_image(struct imv_source *src)
+{
+  GError *error;
+  char path[PATH_MAX+8];
+  snprintf(path, sizeof path, "file://%s", src->name);
+  RsvgHandle *handle = rsvg_handle_new_from_file(path, &error);
+  if (!handle) {
+    report_error(src);
+    return;
+  }
+
+  RsvgDimensionData dim;
+  rsvg_handle_get_dimensions(handle, &dim);
+  src->width = dim.width;
+  src->height = dim.height;
+
+  GdkPixbuf *buf = rsvg_handle_get_pixbuf(handle);
+  if (!buf) {
+    rsvg_handle_close(handle, &error);
+    report_error(src);
+    return;
+  }
+
+  rsvg_handle_close(handle, &error);
+  send_bitmap(src, buf);
+}
+
+static enum backend_result open_path(const char *path, struct imv_source **src)
+{
+  /* Look for an <SVG> tag near the start of the file */
+  char header[128];
+  FILE *f = fopen(path, "rb");
+  if (!f) {
+    return BACKEND_BAD_PATH;
+  }
+  fread(header, 1, sizeof header, f);
+  fclose(f);
+
+  header[(sizeof header) - 1] = 0;
+  if (!strstr(header, "<SVG") && !strstr(header, "<svg")) {
+    return BACKEND_UNSUPPORTED;
+  }
+
+  struct imv_source *source = calloc(1, sizeof(struct imv_source));
+  source->name = strdup(path);
+
+  source->width = 1024;
+  source->height = 1024;
+  source->num_frames = 1;
+  source->next_frame = 1;
+  source->load_first_frame = &load_image;
+  source->load_next_frame = NULL;
+  source->free = &source_free;
+  source->callback = NULL;
+  source->user_data = NULL;
+  source->private = NULL;
+
+  *src = source;
+  return BACKEND_SUCCESS;
+}
+
+static void backend_free(struct imv_backend *backend)
+{
+  free(backend);
+}
+
+struct imv_backend *imv_backend_rsvg(void)
+{
+  struct imv_backend *backend = malloc(sizeof(struct imv_backend));
+  backend->name = "rsvg (LGPL license)";
+  backend->open_path = &open_path;
+  backend->free = &backend_free;
+  return backend;
+}
diff --git a/src/backend_rsvg.h b/src/backend_rsvg.h
new file mode 100644
index 0000000..126892a
--- /dev/null
+++ b/src/backend_rsvg.h
@@ -0,0 +1,9 @@
+#ifndef IMV_BACKEND_RSVG_H
+#define IMV_BACKEND_RSVG_H
+
+struct imv_backend;
+
+/* Create an instance of the rsvg backend */
+struct imv_backend *imv_backend_rsvg(void);
+
+#endif
diff --git a/src/main.c b/src/main.c
index 3f96b02..8b88340 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3,6 +3,7 @@
 #include "backend.h"
 #include "backend_freeimage.h"
 #include "backend_libpng.h"
+#include "backend_rsvg.h"
 
 int main(int argc, char** argv)
 {
@@ -12,6 +13,7 @@ int main(int argc, char** argv)
     return 1;
   }
 
+  imv_install_backend(imv, imv_backend_rsvg());
   imv_install_backend(imv, imv_backend_freeimage());
   imv_install_backend(imv, imv_backend_libpng());
 
-- 
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