It sounds like you're trying to scale around a certain center point: Given a center point (x,y) and scale values sx, sy, you derive translate values tx and ty: tx = -x * (sx - 1.0); ty = -y * (sy - 1.0); translate(tx, ty); scale(sx, sy); Michael Bishop
________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Tue 4/17/2007 4:10 PM To: [email protected] Subject: JSVGCanvas.setRenderingTransform() I hope somebody can shed some light on this. Basically, I want to do in software what could be done with a control-drag-mousebutton1. Seems like there could be a simple interface to call to do this, but I haven't found it yet. I'm trying to implement what I call a "pre-zoomed" SVG file. In my SVG file, I have added an element <x:defaultpicturesize viewBox="x y w h"/>. Since I haven't found a call to "zoom it to this box", I tried using setRenderingTransform(). After loading the SVG file (and after gvtRenderingCompleted() is called), I look for this element. If I find one, I create an AffineTransform and call setRenderingTransform() The problem is that this thing does not do what I expect it to. It is easy enough to center up the picture (if that's all I wanted to do). I simply calculate the difference between the center of the <svg:svg viewbox="..."> and the center of my desired viewbox. This is straightforward and produces a view that looks close to centered (but clearly is not exactly centered). When I apply a scaling transformation things go very off. First of all, scaling appears to happen based on the upper left-hand corner of the picture. For example, if I only scale (say 2x) what previously was in the upper left-hand corner now fills the entire display. So I think, translate the upper left-hand corner of the desired viewbox to the x and y of the <svg:svg> viewbox and then scale. Still not right. Then I think, okay, it's scaling first so my translation values actually need to be multiplied by the scale factor - better but still not right. What am I missing here? Seems like this should be an easy thing to do. Regards, Randy
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