Stop abusing Cairo user data, part 1

This commit temporarily breaks multi-page images and animations.

1 files changed, 90 insertions, 36 deletions

diff --git a/fiv-io.h b/fiv-io.h
index 582b907..9bddedc 100644
--- a/fiv-io.h
+++ b/fiv-io.h
@@ -33,12 +33,98 @@ void fiv_io_profile_free(FivIoProfile self);
 // From libwebp, verified to exactly match [x * a / 255].
 #define PREMULTIPLY8(a, x) (((uint32_t) (x) * (uint32_t) (a) * 32897U) >> 23)
 
+// --- Metadata ----------------------------------------------------------------
+
+// https://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf Table 6
+typedef enum _FivIoOrientation {
+	FivIoOrientationUnknown   = 0,
+	FivIoOrientation0         = 1,
+	FivIoOrientationMirror0   = 2,
+	FivIoOrientation180       = 3,
+	FivIoOrientationMirror180 = 4,
+	FivIoOrientationMirror270 = 5,
+	FivIoOrientation90        = 6,
+	FivIoOrientationMirror90  = 7,
+	FivIoOrientation270       = 8
+} FivIoOrientation;
+
+/// Returns a rendering matrix for a surface (user space to pattern space),
+/// and its target dimensions.
+cairo_matrix_t fiv_io_orientation_apply(cairo_surface_t *surface,
+	FivIoOrientation orientation, double *width, double *height);
+void fiv_io_orientation_dimensions(cairo_surface_t *surface,
+	FivIoOrientation orientation, double *width, double *height);
+
+/// Extracts the orientation field from Exif, if there's any.
+FivIoOrientation fiv_io_exif_orientation(const guint8 *exif, gsize len);
+
+/// Save metadata attached by this module in Exiv2 format.
+gboolean fiv_io_save_metadata(
+	cairo_surface_t *page, const char *path, GError **error);
+
 // --- Loading -----------------------------------------------------------------
 
 extern const char *fiv_io_supported_media_types[];
 
 gchar **fiv_io_all_supported_media_types(void);
 
+typedef struct _FivIoRenderClosure {
+	/// The rendering is allowed to fail, returning NULL.
+	cairo_surface_t *(*render)(struct _FivIoRenderClosure *, double scale);
+	void (*destroy)(struct _FivIoRenderClosure *);
+} FivIoRenderClosure;
+
+typedef struct _FivIoImage {
+	uint8_t *data;                      ///< Raw image data
+	cairo_format_t format;              ///< Data format
+	uint32_t width;                     ///< Width of the image in pixels
+	uint32_t stride;                    ///< Row stride in bytes
+	uint32_t height;                    ///< Height of the image in pixels
+
+	FivIoOrientation orientation;       ///< Orientation to use for display
+
+	GBytes *exif;                       ///< Raw Exif/TIFF segment
+	GBytes *icc;                        ///< Raw ICC profile data
+	GBytes *xmp;                        ///< Raw XMP data
+	GBytes *thum;                       ///< WebP THUM chunk, for our thumbnails
+
+	/// A FivIoRenderClosure for parametrized re-rendering of vector formats.
+	/// This is attached at the page level.
+	FivIoRenderClosure *render;
+
+	/// The first frame of the next page, in a chain.
+	/// There is no wrap-around.
+	struct _FivIoImage *page_next;
+
+	/// The first frame of the previous page, in a chain.
+	/// There is no wrap-around. This is a weak pointer.
+	struct _FivIoImage *page_previous;
+
+	/// The next frame in a sequence, in a chain, pre-composited.
+	/// There is no wrap-around.
+	struct _FivIoImage *frame_next;
+
+	/// The previous frame in a sequence, in a chain, pre-composited.
+	/// This is a weak pointer that wraps around,
+	/// and needn't be present for static images.
+	struct _FivIoImage *frame_previous;
+
+	/// Frame duration in milliseconds.
+	int64_t frame_duration;
+
+	/// How many times to repeat the animation, or zero for +inf.
+	uint64_t loops;
+} FivIoImage;
+
+FivIoImage *fiv_io_image_ref(FivIoImage *image);
+void fiv_io_image_unref(FivIoImage *image);
+
+/// Return a new Cairo image surface referencing the same data as the image,
+/// eating the reference to it.
+cairo_surface_t *fiv_io_image_to_surface(FivIoImage *image);
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 // Userdata are typically attached to all Cairo surfaces in an animation.
 
 /// GBytes with plain Exif/TIFF data.
@@ -51,6 +137,7 @@ extern cairo_user_data_key_t fiv_io_key_icc;
 extern cairo_user_data_key_t fiv_io_key_xmp;
 /// GBytes with a WebP's THUM chunk, used for our thumbnails.
 extern cairo_user_data_key_t fiv_io_key_thum;
+
 /// GHashTable with key-value pairs from PNG's tEXt, zTXt, iTXt chunks.
 /// Currently only read by fiv_io_open_png_thumbnail().
 extern cairo_user_data_key_t fiv_io_key_text;
@@ -74,11 +161,6 @@ extern cairo_user_data_key_t fiv_io_key_page_next;
 /// There is no wrap-around. This is a weak pointer.
 extern cairo_user_data_key_t fiv_io_key_page_previous;
 
-typedef struct _FivIoRenderClosure {
-	/// The rendering is allowed to fail, returning NULL.
-	cairo_surface_t *(*render)(struct _FivIoRenderClosure *, double scale);
-} FivIoRenderClosure;
-
 /// A FivIoRenderClosure for parametrized re-rendering of vector formats.
 /// This is attached at the page level.
 /// The rendered image will not have this key.
@@ -93,9 +175,10 @@ typedef struct {
 	GPtrArray *warnings;                ///< String vector for non-fatal errors
 } FivIoOpenContext;
 
-cairo_surface_t *fiv_io_open(const FivIoOpenContext *ctx, GError **error);
-cairo_surface_t *fiv_io_open_from_data(
+FivIoImage *fiv_io_open(const FivIoOpenContext *ctx, GError **error);
+FivIoImage *fiv_io_open_from_data(
 	const char *data, size_t len, const FivIoOpenContext *ctx, GError **error);
+
 cairo_surface_t *fiv_io_open_png_thumbnail(const char *path, GError **error);
 
 // --- Thumbnail passing utilities ---------------------------------------------
@@ -118,32 +201,3 @@ unsigned char *fiv_io_encode_webp(
 /// If no exact frame is specified, this potentially creates an animation.
 gboolean fiv_io_save(cairo_surface_t *page, cairo_surface_t *frame,
 	FivIoProfile target, const char *path, GError **error);
-
-// --- Metadata ----------------------------------------------------------------
-
-// https://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf Table 6
-typedef enum _FivIoOrientation {
-	FivIoOrientationUnknown   = 0,
-	FivIoOrientation0         = 1,
-	FivIoOrientationMirror0   = 2,
-	FivIoOrientation180       = 3,
-	FivIoOrientationMirror180 = 4,
-	FivIoOrientationMirror270 = 5,
-	FivIoOrientation90        = 6,
-	FivIoOrientationMirror90  = 7,
-	FivIoOrientation270       = 8
-} FivIoOrientation;
-
-/// Returns a rendering matrix for a surface (user space to pattern space),
-/// and its target dimensions.
-cairo_matrix_t fiv_io_orientation_apply(cairo_surface_t *surface,
-	FivIoOrientation orientation, double *width, double *height);
-void fiv_io_orientation_dimensions(cairo_surface_t *surface,
-	FivIoOrientation orientation, double *width, double *height);
-
-/// Extracts the orientation field from Exif, if there's any.
-FivIoOrientation fiv_io_exif_orientation(const guint8 *exif, gsize len);
-
-/// Save metadata attached by this module in Exiv2 format.
-gboolean fiv_io_save_metadata(
-	cairo_surface_t *page, const char *path, GError **error);