From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Tue, 1 Sep 2015 23:02:38 +0000 (+0200)
Subject: Propagate size correctly across effects that change output size.
X-Git-Tag: 1.2.0~32
X-Git-Url: https://git.sesse.net/?p=movit;a=commitdiff_plain;h=4a35c01ed5407a3d9b9616f9d13e77970ee003ef;ds=sidebyside

Propagate size correctly across effects that change output size.

When propagating size information between effects in a phase,
we'd forget to check if the effect wanted to change size
and use that information instead of our own heuristics.
Fix that.

This is currently a no-op, since right now we always break a phase
when an effect changes output size, but there are very real situations
where we'd be fine with not doing so, so this patch paves the way
for that.
---

diff --git a/effect_chain.cpp b/effect_chain.cpp
index d33cdae..870da81 100644
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -623,7 +623,8 @@ void EffectChain::inform_input_sizes(Phase *phase)
 	// Now propagate from the inputs towards the end, and inform as we go.
 	// The rules are simple:
 	//
-	//   1. Don't touch effects that already have given sizes (ie., inputs).
+	//   1. Don't touch effects that already have given sizes (ie., inputs
+	//      or effects that change the output size).
 	//   2. If all of your inputs have the same size, that will be your output size.
 	//   3. Otherwise, your output size is 0x0.
 	for (unsigned i = 0; i < phase->effects.size(); ++i) {
@@ -645,8 +646,16 @@ void EffectChain::inform_input_sizes(Phase *phase)
 				this_output_height = 0;
 			}
 		}
-		node->output_width = this_output_width;
-		node->output_height = this_output_height;
+		if (node->effect->changes_output_size()) {
+			// We cannot call get_output_size() before we've done inform_input_size()
+			// on all inputs.
+			unsigned real_width_ignored, real_height_ignored;
+			node->effect->get_output_size(&real_width_ignored, &real_height_ignored,
+			                              &node->output_width, &node->output_height);
+		} else {
+			node->output_width = this_output_width;
+			node->output_height = this_output_height;
+		}
 	}
 }