Tom, I think what you're talking about is definitely possible, we've talked about it before. I think one of the hardest cases is dealing with complex paths with transparent gradients -- but it is solvable too. I don't believe that anyone is currently working on it though. If you'd like to, I can give you some pointers about where to start looking in the code. --Ted On Thu, 2005-09-29 at 09:29 -0700, Tom Epperly wrote: >I wonder if you've considered an interim solution to generating better >EPS files and PDFs for Inkscape drawings with transparent bitmaps. I >would like to run and idea past you. I am unfamiliar with Inkscape from >a developers perspective, so it may be worthless. In case it's not, here >goes. > >If we exclude bitmaps which are rotated or skewed, it seems that one >could use Inkscape's SVG -> bitmap capability (demonstrated by the PNG >export) to resolve the transparency and generate a resolved bitmap that >could be used instead of the original tranparent bitmap when producing >the EPS/PDF. If a transparent bitmap covers the rectangle defined by its >corners (x1, y1) to (x2,y2), you can calculate the dots per inch of the >in the x and y dimension taking into account any scaling applied by the >user. Use Inkscape to render a bitmap of the rectangle (x1,y1) to (x2, >y2) at the maximum of resolution (perhaps min {300, max {x_resolution, >y_resolution}}). Use this bitmap instead of the orignal when creating >the PDF. > >Of course, this idea can be improved upon. For example during the bitmap >rendering phase, it would be better to render only the bitmap and >elements below it (i.e., things that could actually appear in the >transparent parts of the bitmap and not things above). If SVG's bitmap >renderer can have different x and y resolutions, match the original >bitmaps x and y resolutions. Alternatively, you could render the bitmap >at a higher resolution to make sure the background elements that show >through the transparent parts appear smooth at reasonable printing >resolutions. > >I suppose you could even handle scaled, rotated and skewed bitmaps by >rendering at high resolution a box that includes the whole scaled, >rotated and/or skewed bitmap. Then take the resolved bitmap and undo the >scale, skew and/or rotation to generate an unperturbed bitmap that when >scaled, rotated and/or skewed will produce the contents that the >renderer produced. I am guessing that in 90% of the situations, bitmaps >aren't rotated or skewed, so it may not be worth solving the general >problem. > >Well, what do you think? I recently made a poster with a radial gradient >as the background and several logos (tranparent bitmaps) were on top of >the gradient. I ended up exporting as a high resolution PNG, converting >to TIFF and then converting TIFF2PDF. Inkscape looks like a fine program. > >Tom > > >------------------------------------------------------- >This SF.Net email is sponsored by: >Power Architecture Resource Center: Free content, downloads, discussions, >and more. http://solutions.newsforge.com/ibmarch.tmpl >_______________________________________________ >Inkscape-devel mailing list >Inkscape-devel(a)lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/inkscape-devel > >

On 9/29/05, Tom Epperly <tepperly@...1012...> wrote: >I wonder if you've considered an interim solution to generating better >EPS files and PDFs for Inkscape drawings with transparent bitmaps. I >would like to run and idea past you. I am unfamiliar with Inkscape from >a developers perspective, so it may be worthless. In case it's not, here >goes. > > As far as I understand from your description, what you suggest is changing the way we treat bitmap objects on export to PS - is this correct? If so it is possible, but it will fix only a small part of all problems with transparency in PS. Regular vector objects with transparency are much more common than transparent bitmaps. As I already said here, my personal view is that it's not worth it to spend effort on improving PS export with regard to transparency (any such improvements are bound to be more or less hacks). Instead, it's better to spend the same resources on supporting PDF with native transparency.

-- bulia byak Inkscape. Draw Freely. http://www.inkscape.org

On 9/30/05, Tom Epperly <tepperly@...1012...> wrote: > I did a little WWW searching, and I see that "PostScript 3 technology > delivers support for transparent artwork in PDF 1.4 and 1.5 and support > for JPEG 2000 and layers in PDF 1.5." I know Postscript up to level 2, > but I can't seem to find any detailed (non-marketing) descriptions of > what operators they added in level 3. Yeah, marketing descriptions are generally misleading, but this one is particularly confusing. I believe what they meant to say is that true transparency is in PDF 1.4+, and that is somehow based on PS3, so by some twist, PS3 can be said to "deliver" it even though it does not support it itself. Anyway, to get the manual for PS3, google for plrm.pdf. From when I read it, I remember they added some sort of bitmap transparency masks for bitmaps, but not even flat semi-transparency for regular vector objects. Which, to me, means it's almost useless.