I use the path data generated by Inkscape in my Flex applications. The data from Inkscape maps perfectly to the Flex Framework's Path class, and I suggest you check out the technique if you ever play around with Flex.

One problem I've run into while doing this is that sometimes the coordinates in the inkscape path data appear way out of bounds. For example, here is the data for an arbitrary path created by Inkscape:



The path dimensions are 362 x 270 pixels, and the path coordinates are 0,0. This makes me ask why does the initial M command start at 0,1052.3622? That point is not inside the path's coordinate space. This doesn't map well to a Flex path, as the point usually falls outside my application dimensions.

The only fix I've found is to move the path to 0,1052.3622 in Inkscape before moving the data to Flex, in which case the M command reads M 0,-2e-5, which is close enough to change it to 0,0.

Anyone know why these command coordinates are so far out of bounds, and have a suggestion to fix them? If I start a path at 0,0 then I'd like the M command to be 0,0.

Revisited and marked as [ off-topic ] a few hours later - see next comment...

Also note that Inkscape currently uses a different internal co-ordinate system than SVG (y axis is flipped) which means that things like the pages origin in Inkscape may not co-inside with (0,0) of the SVG document. This is a long-standing issue which the developers want to change, but it takes time.

tomh wrote:Also note that Inkscape currently uses a different internal co-ordinate system than SVG (y axis is flipped)

You are right, that's far more likely what is happening! My previous answer isn't relevant here at all (I misread the coordinates, my bad!)

Thank you both for your speedy replies!

I'm aware that the 0,0 SVG origin is at the top left corner, and the 0,0 Inkscape origin is at the bottom left corner, and that a positive y value in SVG results in a lower screen position, while a positive y value in Inkscape results in a higher screen position. I originally thought this might be the source of my problem, but even this doesn't account for the huge discrepancy in y values.

I'll attempt to clarify the problem a little more clearly. Say I create a new document with the dimensions 200 x 150 pixels, and I use the pen tool to start a path at 0,0. I continue drawing the path within the 200 x 150 coordinate space, and never deviate from this space. At this stage, when I check the path data in the XML Editor it appears to be correct, with M values of 0,0 and L and C values all within the space of 200 x 150 pixels. After these steps, I can transfer the data to a Flex Path and it works great. But if I start moving the nodes or control points around, in Inkscape, to achieve the desired path shape, then check the data again, the M command has usually changed to something like this, M 0,1532.3662. It seems the x value always stays at 0 but y-value changes to 1000+. Once this happens, the only way I can correct the data so it still works in Flex is to either undo all my little tweaks until the original data is back, or I can move the path (either by changing the y-value input or dragging the path) to the y-value in the M command. Once I do this, the M command reads M 0,0 and the data maps to Flex again.

I guess my question is, if a path starts at 0,0, and I tweak any of the path nodes, but I DONT move the original point, why does the M command y-value change to a value of somewhere between 1000 and 1600 pixels, and subsequently why do all the L and C command y-values increase relatively?

I wonder if your preferences are set to store relative instead of optimized paths? (under inkscape preferences/svg output/path data/allow relative coordinates)?

amffma wrote:Say I create a new document with the dimensions 200 x 150 pixels,

Resizing the page adds a 'transform' attribute to the existing top-level layers.

When you first draw a path with the pen tool inside such a 'transformed' layer, the path has an explicit 'transform' attribute too, on the next move of the path with the select tool, the explicit 'transform' attribute of the path is converted into 'optimized' path data i.e. the coordinates are recalculated to incorporate the transformation (watch it happen live, in Inkscape's XML Editor).

To avoid this issue, create a new layer after resizing the page and draw your path on the new layer. The new (empty) layer will not need the 'transform' attribute and the coordinates of paths drawn on the new layer should be precisely as you expect them.

@~suv Amazing! This absolutely did the trick. It also explains why the problem occurred only some of the time. I didn't realize it only happened when I re-sized the document. Thanks for the help mate!

@druban & @tomh Thanks for the suggestions!

@everyone Feel free to ignore the redundant and nonsensical line:

amffma wrote:I'll attempt to clarify the problem a little more clearly.