Blending Objects with Bitmap Fills Along a Path

Dear TalkGraphics Gurus,

I continue to be impressed by Xara Xtreme! And I really appreciate the fine help I received with my first question. Now it's time for the next challenge!

I have been playing with blends a little bit more. I really like that I can apply them to photos as well as vector objects. However I seem to have hit up against a problem. If I blend one photo to another, it works fine until I try to additionally blend along a curve. If I try to blend along a curve, the bitmap fill go haywire.

To reproduce this behavior, do the following:

1) Open a new document and paste in a photo. Position it in the lower left.
2) Duplicate the photo. Make it smaller and position it in the upper-right.
3) Blend from the first photo to the second one.

Note that the blend looks very nice and will behave properly if you change either endpoint object. Now,

4) Draw a curve over the blend.
5) Select both the curve and the blend, then click the blend tool.
6) Click the "Blend Along a Curve" button.

Notice that the bitmap fill is no longer behaving properly:

http://wjm.org/linked/blendgoof.jpg

Is this a bug? A limitation? Or is there an option I haven't learned yet to keep the bitmap fill in proper relationship to its bounding box?

Bill

This appears to be a bug. It also happens with the 3 and 4 colour fills and with fractal fills (which are effectively bitmap fills).

It will be logged as a bug and fixed in due course.

Gerry Iles

It’s not a bug. Xara's blend tool blends vectors, not bitmaps. In the help file, there is help associated with techniques to quasi-blend bitmaps. Alternatively, you could trace the bitmaps into vector compilations, and blend those.

I'm sorry but it is a bug. The control points of the bitmap fills should be being blended along the curve but they are actually blended straight. The attached file shows a blend along a curve between two rectangles with a bitmap fill. It has been converted to editable shapes and ungrouped. If you select each rectangle in turn and look at the fill applied you can clearly see that the fills have been blended in a straight line rather than along the curve.

I believe you are getting confused with the envelope tool which doesn't distort the bitmap.

Gerry Iles

The control points are bitmap fill points, and are not blended - they are not vector shape points. Although vector fills like circular etc are blended. It might be interesting to see what Xara say if you report it anyway, but I think that because it is bitmap associated, the blend tool does not consider it - but maybe it should to some extent.

Hello Xhris,

I do know what I am talking about, I am one of the programmers at Xara. As I said in an earlier message, the problem also occurs with 3 and 4 colour fills.

Gerry Iles

Ok. Excuse my presumptuousness. I always assumed this was normal behaviour, otherwise I would have reported it long ago. Lesson (again...): I shouldn't make assumptions.

Here's a good work around anyway. Create a brush out of the bitmap, then you can select brush options to not tile fills, and not rotate about the line. Then you effectively get the desired result - a "blend" along a curve.

The blend tool certainly does consider the bitmap fill. Consider the following example where I have traced the car carefully and rotated one of the blend endpoints:

http://wjm.org/linked/blendgoof2.jpg

As you can see, the raster fill matches the vector outline precisely in each iteration. The blend on a curve option is merely arranging the shapes differently, as depicted in the upper-left.

Either the non-curved behavior is a bug, or the curved behavior is. Personally I prefer the image fill to stick with the outline, so I vote that the curved behavior is a bug.

Merry

p.s.: As I preview my post I see that I'm chiming in late (took me a while to prepare the sample file). Also, I'm delighted to see the Xara team reads and participates in the forum. Thank you for picking up the bug, Gerry, and I hope it is solved soon. Way to go, Xara!

Thanks a lot Gerry1,

I already told it directly to Xara team some times ago and their answer was the same than yours. Another similar bug that was clearly solved with X1 was the wrong resizing of bitmap fills in brushes. Thus I am confident that the present one will be solved too.

kindly,
ivan

Quote:

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Originally Posted by GerryI

This appears to be a bug. It also happens with the 3 and 4 colour fills and with fractal fills (which are effectively bitmap fills). It will be logged as a bug and fixed in due course.

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Unfortunately, I see this problem still persists in Xara Xtreme Pro. :( I guess "due course" means "a year and a half or more?"