On Jun 6, 2014, at 11:38 PM, Rik Cabanier <caban...@gmail.com> wrote:
> > > > On Fri, Jun 6, 2014 at 2:34 PM, Dirk Schulze <dschu...@adobe.com> wrote: > > On Jun 6, 2014, at 11:22 PM, Rik Cabanier <caban...@gmail.com> wrote: > > > > > The issue is not that "isIdentity()" is confusing. The problem is that you > > shouldn't make decisions based on it. From earlier in the thread: > > > > The isIdentity() method has the same issue as was described about is2D() > > above: as matrices get computed, they are going to jump unpredicably > > between being exactly identity and not. People using isIdentity() to jump > > between code paths are going to get unexpected jumps between code paths > > i.e. typically performance cliffs, or worse if they start asserting that a > > matrix should or should not be exactly identity. For that reason, I would > > remove the isIdentity method. > > And as real world examples show (browser implementations, graphic libraries > and even game engines). This is not really an issue in practice. > > It *is* an issue. Check all the cases in WebKit where you're checking for > "almost" identity. > In all these cases WebKit does the same as all other browser engines, graphic libraries and game engines. We take the long way and compute transformations as if the matrix is not identity (which it actually isn’t)! I do not see the issue that you mention. Greetings, Dirk _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
