Update some comments

1 files changed, 5 insertions, 60 deletions

diff --git a/fragment.c b/fragment.c
index a8e0f52..ae01e9a 100644
--- a/fragment.c
+++ b/fragment.c
@@ -138,28 +138,9 @@ state_composite (state_t *dest, pixman_op_t op, state_t *source)
     if (!new_state)
 	return NULL;
     
-    /* This function conceptually returns a new object. However,
-     * in order to optimize, we will want to to do copy-on-write
-     * whenever possible
+    /* FIXME: Always using COMMAND should be correct, but
+     * we can do a lot better with a few simple optimizations
      */
-    /* It is always correct to make a copy of dest and source, and
-     * use them in a command buffer. That in turn implies that a
-     * command buffer holds a ref on all the images involved.
-     */
-    /* Actually a composite command should most likely be considered
-     * to have implicit destination and one source. That's what the callers
-     * are going to want:
-     *
-     *       clip_image = create_clip_image()
-     *       dest_image = create_dest_image()
-     *       composite (dest_image, DEST_OUT, clip_image);
-     *       etc.
-     */
-    /* Hence, for a new state, we should start by SRCing dest onto
-     * the new image, and then apply the composite.
-     */
-
-    /* FIXME: optimize here */
     new_state->common.type = STATE_COMMAND;
     new_state->common.ref_count = 1;
 
@@ -384,44 +365,6 @@ state_apply (state_t *state, pixman_image_t *image)
 	break;
 
     case STATE_COMMAND:
-	/* FIXME: hmm this has to be broken because it doesn't ever
-	 * create a temporary image.
-	 */
-	/* The correct thing here may be to
-	 * - SRC source onto temp image a
-	 * - SRC dest onto temp image b
-	 * - apply a op b
-	 * - SRC b onto image
-	 *
-	 * which simplifies to
-	 *  - SRC source onto temp image
-	 *  - SRC dest into image
-	 *  - apply source to image
-	 *
-	 * In the case where source is just a "foo IN bar",
-	 * we can simpify to "apply (foo, bar, dest)".
-	 *
-	 * The correct thing is actually to:
-	 *     - copy dest to a temp image
-	 *     - composite SRC onto temp using command.op
-	 *     - composite temp onto image using argument op.
-	 *
-	 * which simplifies a bit if one or both of the ops is SRC
-	 * if both: simply SRC source onto image
-	 * if op, but not comamnd.op:
-	 *     SRC dst onto image, then source command.op onto image.
-	 * if command.op, but not op:
-	 *     apply source to image using command.op
-	 * These optimizations should probably take place at
-	 * composite time, not apply time.
-	 */
-	/* What if there is no arg-op (or equivalently defined to be SRC? 
-	 * Then the answer is
-	 *     - apply dest to image
-	 *     - create temp image
-	 *     - apply source to temp
-	 *     - composite temp with command op to image
-	 */
 	/* FIXME: track alpha-only */
 	temp = pixman_image_create_bits (
 	    PIXMAN_a8r8g8b8, width, height, NULL, -1);
@@ -431,7 +374,9 @@ state_apply (state_t *state, pixman_image_t *image)
 	
 	state_apply (state->command.dest, image);
 
-	/* FIXME: check if source can be expressed as (s IN m) */
+	/* FIXME: check if source can be expressed as
+	 * (s IN m), (s IN glyphs), (s IN traps)
+	 */
 	state_apply (state->command.source, temp);
 
 	pixman_image_composite32 (