23243 2009-01-11 13:04:26 -0800 Need to add multLeft() to TransformationMatrix and WebKitCSSMatrix 2010-09-20 20:58:01 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Mac OS X 10.5 RESOLVED FIXED P2 Normal --- 1 simon.fraser cmarrin dino jeffschiller oldest_to_newest 105257 0 simon.fraser 2009-01-11 13:04:26 -0800 TransformationMatrix::multiply() does a multRight with the supplied matrix. The other operations, like scale(), are applied to the left (as expected). I think TransformationMatrix needs explicit multLeft and multRight (or pre- and post-multiply). 105606 1 cmarrin 2009-01-13 16:48:45 -0800 I don't think it's really necessary to have both variants. This is usually provided as an optimization, since the operation is self-modifying. Today, if you wanted to multiply b * a, but put the result in a, you would have to: TransformationMatrix tmp = b; a = tmp.multiply(a); Which isn't that bad. Alternatively, we could change to a non-destructive multiply, which would ALWAYS be more inefficient, rather than just when you need to flip the operation order. I don't think our use of TransformationMatrix is extensive enough to warrant this. 105625 2 simon.fraser 2009-01-13 17:39:09 -0800 We have determined that SVGMatrix's multiply() is a multRight(), which also does not match its scale() etc, and indeed we think that TransformationMatrix should be more explicit about left vs. right multiply. 106089 3 cmarrin 2009-01-16 10:56:55 -0800 Now multiply() does a multRight() in TransformationMatrix, CSSMatrix and SVGMatrix. I think we should leave it that way for compatibility and add a multLeft() function (at least to TransformationMatrix and CSSMatrix). 160439 4 jeffschiller 2009-11-04 08:02:31 -0800 I'm ready and willing to hack - does anyone care to mentor me through this and Bug 16062? Is there a good IRC channel to ask questions? 160441 5 simon.fraser 2009-11-04 08:05:35 -0800 Find me (smfr) on #webkit later today. 160463 6 jeffschiller 2009-11-04 09:21:21 -0800 In looking at the source, TransformationMatrix now has an explicit multLeft() and a multiply(), which does a multRight. This was done by cmarrin for Bug 6868 and landed r40761. I will fix SVGMatrix's incorrect matrix multiplication as part of Bug 16062. Is there anything left to do for this bug? 282065 7 jeffschiller 2010-09-20 20:56:23 -0700 smfr: I think this bug can be closed, do you agree? 282066 8 simon.fraser 2010-09-20 20:58:01 -0700 Yes.