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Fix matrixMultiply() to properly seek rotate/scales

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git-svn-id: http://svg-edit.googlecode.com/svn/branches/transformlist@929 eee81c28-f429-11dd-99c0-75d572ba1ddd
This commit is contained in:
Jeff Schiller
2009-11-11 07:42:23 +00:00
parent 55f791910a
commit 70745df23a
1 changed files with 73 additions and 72 deletions
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145
editor/svgcanvas.js
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@@ -1388,28 +1388,52 @@ function BatchCommand(text) {
// if it's a group, we have special reduction loops to flatten transforms
if (selected.tagName == "g") {
// always remove translates by transferring them down to the children
// otherwise just reduce adjacent scales
// The first pass is to collapse all adjacent translates and push
// them down to the children
var n = tlist.numberOfItems;
// loop through transforms and accumulate translation and scaling
var mat = svgroot.createSVGMatrix();
var bFoundRotate = false;
n = tlist.numberOfItems;
while (n--) {
var xform = tlist.getItem(n);
// only flatten the translate if it is not before or after a scale
if (xform.type != 2 || (n < (tlist.numberOfItems-1) && tlist.getItem(n+1).type == 3) ||
(n > 0 && tlist.getItem(n-1).type == 3))
{
continue;
if (xform.type == 4) {
// update the frame of reference
mat = matrixMultiply(xform.matrix, mat);
bFoundRotate = true;
// break;
}
// accumulate the transformed translation
else if (xform.type == 2) {
// get the centroid of scaling and determine the net translation for this scale
var tobj = transformToObj(xform);
if (bFoundRotate && false) {
tx += tobj.tx;
ty += tobj.ty;
}
else {
var t = transformPoint(tobj.tx, tobj.ty, mat.inverse());
// accumulate translation
tx += t.x;
ty += t.y;
}
tlist.removeItem(n);
}
// if it's a scale, we accumulate it
else if (xform.type == 3) {
// update the frame of reference
mat = matrixMultiply(mat, xform.matrix);
// accumulate the scale values
var sobj = transformToObj(xform);
sx *= sobj.sx;
sy *= sobj.sy;
var tobj = transformToObj(xform);
tx += tobj.tx;
ty += tobj.ty;
// remove the translate from the group
tlist.removeItem(n);
tlist.removeItem(n);
}
}
// now restore just the one translate
// force the accumulated translation down to the children
if (tx != 0 || ty != 0) {
// we pass the translates down to the individual children
var children = selected.childNodes;
@@ -1426,56 +1450,7 @@ function BatchCommand(text) {
}
}
// The second pass is to find all adjacent transform sets of the form:
// translate(tx,ty) scale(sx,sy) translate(-tx,-ty) and collapse them by
// applying the translates to the children and accumulating the scale factors
var mat = svgroot.createSVGMatrix();
n = tlist.numberOfItems;
while (n--) {
var xform = tlist.getItem(n);
// we stop as soon as we encounter a rotate
if (xform.type == 4) {
// update the frame of reference
mat = matrixMultiply(mat, xform.matrix);
break;
}
// if it's a translate we push it to the children
else if (xform.type == 2) {
// get the centroid of scaling and determine the net translation for this scale
var tobj = transformToObj(xform);
var t = transformPoint(tobj.tx, tobj.ty, mat.inverse());
// we pass the translates down to the individual children
var children = selected.childNodes;
var c = children.length;
while (c--) {
var child = children.item(c);
if (child.nodeType == 1) {
var childTlist = canvas.getTransformList(child);
var newxlate = svgroot.createSVGTransform();
newxlate.setTranslate(t.x, t.y);
childTlist.insertItemBefore(newxlate, 0);
batchCmd.addSubCommand( recalculateDimensions(child) );
}
}
tlist.removeItem(n);
}
// if it's a scale, we accumulate it
else if (xform.type == 3) {
// update the frame of reference
mat = matrixMultiply(mat, xform.matrix);
// accumulate the scale values
var sobj = transformToObj(xform);
sx *= sobj.sx;
sy *= sobj.sy;
tlist.removeItem(n);
}
}
// now restore just the one scale
// now apply only one scale
if (sx != 1 || sy != 1) {
var newscale = svgroot.createSVGTransform();
newscale.setScale(sx,sy);
@@ -2034,9 +2009,13 @@ function BatchCommand(text) {
return { x: m.a * x + m.c * y + m.e, y: m.b * x + m.d * y + m.f};
};
// This is provided because WebKit doesn't implement multiply() correctly
// matrixMultiply() is provided because WebKit didn't implement multiply() correctly
// on the SVGMatrix interface. See https://bugs.webkit.org/show_bug.cgi?id=16062
// It returns a SVGMatrix that is the multiplication m1*m2.
// This function tries to return a SVGMatrix that is the multiplication m1*m2.
// As far as I can tell, there is no way for us to handle matrix multiplication
// of arbitrary matrices because we cannot directly set the a,b,c,d,e,f values
// of the resulting matrix, we have to do it with translate/rotate/scale
// TODO: investigate if webkit allows direct setting of matrix.a, etc
var matrixMultiply = function(m1, m2) {
var a = m1.a*m2.a + m1.c*m2.b,
b = m1.b*m2.a + m1.d*m2.b,
@@ -2044,11 +2023,33 @@ function BatchCommand(text) {
d = m1.b*m2.c + m1.d*m2.d,
e = m1.a*m2.e + m1.c*m2.f + m1.e,
f = m1.b*m2.e + m1.d*m2.f + m1.f;
// now construct a matrix by analyzing a,b,c,d,e,f and trying to
// translate, rotate, and scale the thing into place
var m = svgroot.createSVGMatrix();
var sx = 1, sy = 1, angle = 0;
// translate
m = m.translate(e,f);
m = m.scaleNonUniform(a,d);
m = m.skewX( Math.atan(c) );
m = m.skewY( Math.atan(b) );
// see if there was a rotation
var rad = Math.atan2(b,a);
if (rad != 0 && rad != Math.PI && rad != -Math.PI) {
m = m.rotate(180.0 * rad / Math.PI);
sx = b / Math.sin(rad);
sy = -c / Math.sin(rad);
}
else { // in the case of no rotation, scales are simply a,d
sx = a;
sy = d;
}
// scale
if (sx != 1 || sy != 1) {
m = m.scaleNonUniform(sx,sy);
}
// TODO: handle skews?
return m;
}