Status: Accepted Owner: siguc...@gmail.com New issue 3770 by siguc...@gmail.com: Gradient fills failure http://code.google.com/p/pharo/issues/detail?id=3770 Modifications to Morphic gradients fail in current versions of Squeak (and Pharo). Using the halo menu to change the first or last color of a morph doesn't work. Despite changes to these colors, the initial gradient remains. I've traced the problem to false hits in GradientFillStyle's LRUCache. LRUCache acts similar to a dictionary. It uses a key and it's hash to store and retrieve values. GradientFillStyle uses uses its colorRamp--a mutable array of associations--as the key to the cache, for instance: {0.0->Color white. 1.0->Color red}. Subsequent modifications to colorRamp also changes the key IN the cache. This can result in false hits. This fault has always been present. Recent changes to the hash calculation in Associations increased its frequency. Association hash has been simplified to return the key. As a result all gradients created from the user interface have the same hash. Since the the lookup == the key and the hashes are the same, false hits are inevitable. To illustrate the problem execute the script below. The first two changes are done using the classes colorRamp modification function. Rather than modifying, the last change replaces colorRamp with a new one. Clearly the first item in the pixelRamp should change when the first color changes. gradient := GradientFillStyle new colorRamp: {0.0->Color red. 1.0->Color white}. Transcript << 'first item for: '; << gradient colorRamp printString; space; << gradient pixelRamp first; cr; flush. gradient firstColor: Color green forMorph: nil hand: nil. Transcript << 'first item for: '; << gradient colorRamp printString; space; << gradient pixelRamp first; cr; flush. gradient firstColor: Color yellow forMorph: nil hand: nil. Transcript << 'first item for: '; << gradient colorRamp printString; space; << gradient pixelRamp first; cr; flush. Transcript show: 'Now replace with a new colorRamp'; cr. newRamp := gradient colorRamp deepCopy. newRamp first value: Color black. gradient colorRamp: newRamp. Transcript << 'first item for: '; << gradient colorRamp printString; space; << gradient pixelRamp first; cr; flush. Results: first item for: {0.0->Color red . 1.0->Color white} 4294901760 first item for: {0.0->Color green . 1.0->Color white} 4294901760 first item for: {0.0->Color yellow . 1.0->Color white} 4294901760 Now replace with a new colorRamp first item for: {0.0->Color black . 1.0->Color white} 4278190081 What's the best way to fix this? Handing out your internals seems ill advised. I think GradientFillStyle should pass a deepCopy of colorRamp to LRUCache. Another solution is for LRUCache to make a deepCopy itself. This would provide protection for all users of LRUCache...provided that deepCopy will always be sufficient. Glen -- View this message in context: http://forum.world.st/Gradient-Fills-Failures-tp3330016p3330016.html Sent from the Squeak - Dev mailing list archive at Nabble.com.