<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> <div class="moz-cite-prefix">I did some more research and ltrace'd pdftocairo --pdf and --png.</div> <div class="moz-cite-prefix">There is no obvious difference in the cairo call that generate the highlight.</div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix">Next, I compared the cairo commands producing the first highlight ("small") with those of the second highlight ("Virtual Mechanics"). Apart from some differing address, the only major difference is an additional cairo_pattern_destroy:<br> </div> <div class="moz-cite-prefix"><font face="monospace"><br> </font></div> <font face="monospace">[...cairo_clip, etc....]<br> // CairoOutputDev::beginTransparencyGroup<br> // <a class="moz-txt-link-freetext" href="https://github.com/freedesktop/poppler/blob/bc4a0d9a2abfcd75d9b0ee4be3f7600905fe6001/poppler/CairoOutputDev.cc#L906">https://github.com/freedesktop/poppler/blob/bc4a0d9a2abfcd75d9b0ee4be3f7600905fe6001/poppler/CairoOutputDev.cc#L906</a><br> cairo_get_matrix(0x56e2e080, 0x56eabc08, 2, 0xf7095466) = 0x56eabc08<br> cairo_push_group(0x56e2e080, 0x56eabc08, 2, 0xf7095466) = 0<br> cairo_set_operator(0x56e2e080, 2, 2, 0xf7095466) = 0<br> cairo_save(0x56e2e080, 0, 0xf79509a9, 0xf7b55184) = 0<br> cairo_pattern_reference(0x56e2e830, 0, 0xf79509a9, 0xf7b55184) = 0x56e2e830<br> cairo_pattern_reference(0x56e2e830, 0, 0xf79509a9, 0xf7b55184) = 0x56e2e830<br> cairo_pattern_get_type(0x56e2e830, 0x56eac04c, 0xffd4a260, 0xf791e9f8) = 0<br> cairo_pattern_destroy(0x56e2e830, 0x56eac04c, 0xffd4a260, 0xf791e9f8) = 10<br> <br> cairo_pattern_create_rgba(0, 0x3ff00000, 0, 0x3ff00000) = 0x56eab410<br> cairo_new_path(0x56e2e080, 0, 0, 7) = 0<br> cairo_move_to(0x56e2e080, 0x28f5c290, 0x405b5f5c, 0x51eb851f) = 0<br> cairo_curve_to(0x56e2e080, 0xcccccccd, 0x405acccc, 0xc28f5c29) = 0<br> cairo_line_to(0x56e2e080, 0xeb851eb8, 0x40614851, 0x8f5c28f6) = 0<br> cairo_curve_to(0x56e2e080, 0x9999999a, 0x40619199, 0x1eb851eb) = 0<br> cairo_set_fill_rule(0x56e2e080, 0, 0x56eabfd0, 0x56eabbb0) = 0<br> cairo_set_source(0x56e2e080, 0x56eab410, 0x56eabfd0, 0x56eabbb0) = 0<br> cairo_fill(0x56e2e080, 0x56eab410, 0x56eabfd0, 0x56eabbb0) = 0<br> cairo_restore(0x56e2e080, 744, 0xf78ea873, 0x56594bdc) = 0<br> cairo_pattern_destroy(0x56eab410, 744, 0xf78ea873, 0x56594bdc) = 0<br> cairo_pattern_destroy(0x56e2e830, 744, 0xf78ea873, 0x56594bdc) = 9<br> <br> cairo_set_operator(0x56e2e080, 2, 2, 0x565abb00) = 0<br> // Next line is only present for the second highlight -> CairoOutputDev::endTransparencyGroup<br> cairo_pattern_destroy(0x56e30cd0, 0xf78ffab0, 0xf78f46b9, 0xf7b55184) = 0<br> cairo_pop_group(0x56e2e080, 0xf78ffab0, 0xf78f46b9, 0xf7b55184) = 0x56e30cd0 // (retval same for both!)<br> cairo_restore(0x56e2e080, 0xf78ffab0, 0xf78f25e9, 0x56594bdc) = 0<br> cairo_pattern_destroy(0x56e2e830, 0xf78ffab0, 0xf78f25e9, 0x56594bdc) = 8<br> cairo_pattern_destroy(0x56e2e830, 0xf78ffab0, 0xf78f25e9, 0x56594bdc) = 7<br> <br> // CairoOutputDev::paintTransparencyGroup<br> cairo_set_operator(0x56e2e080, 14, 0xf7b55184, 0x565abb00) = 0<br> cairo_save(0x56e2e080, 0xffd4a6e4, 0xf78f4889, 0x56597a6c) = 0<br> cairo_set_matrix(0x56e2e080, 0x56eabc08, 0xf78f4889, 0x56597a6c) = 0<br> cairo_set_source(0x56e2e080, 0x56e30cd0, 0xf78f4889, 0x56597a6c) = 0<br> cairo_paint_with_alpha(0x56e2e080, 0, 0x3ff00000, 0x56597a6c) = 0<br> cairo_status(0x56e2e080, 0, 0x3ff00000, 0x56597a6c) = 0<br> _ZdlPvj(0x56eabc00, 60, 0x3ff00000, 0x56597a6c) = 0<br> cairo_restore(0x56e2e080, 60, 0x3ff00000, 0x56597a6c) = 0<br> <br> cairo_restore(0x56e2e080, 32, 0xf78f25e9, 0x56594bdc) = 0<br> cairo_pattern_destroy(0x56e2e830, 32, 0xf78f25e9, 0x56594bdc) = 6<br> cairo_pattern_destroy(0x56e2e830, 32, 0xf78f25e9, 0x56594bdc) = 5<br> <br> cairo_set_operator(0x56e2e080, 2, 0xf7b55184, 0x565abb00) = 0<br> cairo_restore(0x56e2e080, 744, 0xffd4add4, 0x56594bdc) = 0<br> cairo_pattern_destroy(0x56e2e830, 744, 0xffd4add4, 0x56594bdc) = 4<br> cairo_pattern_destroy(0x56e2e830, 744, 0xffd4add4, 0x56594bdc) = 3</font><br> <br> <div class="moz-cite-prefix">I believe cairo_set_operator(,14,) in paintTransparencyGroup should output a gs change in BOTH cases, but it's only for the first case when using a PDF surface; OTOH, when the context is backed by a Image surface, CAIRO_OPERATOR_MULTIPLY is honored also for the second highlight...</div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix"> Tobias<br> </div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix">On 03/11/2022 14:53, Tobias Hoffmann wrote:<br> </div> <blockquote type="cite" cite="mid:a4f6fb9a-d16d-30b3-d483-846356c81b81@thax.hardliners.org"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <div class="moz-cite-prefix"> <div class="moz-cite-prefix">cairo 1.16.0 also exhibits the problem.<br> </div> </div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix">AFAICT the difference between "small" and "Virtual Mechanics" in the content stream (obj 4) is that only for the "small" an additional "/b14 gs" command is present:<br> </div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix">[...]<br> </div> <div class="moz-cite-prefix">q<br> 106.926 93.812 33.621 13.883 re W n<br> /b14 gs<br> q<br> 1 0 0 1 106 93 cm<br> /a0 gs /x7 Do<br> Q<br> Q q<br> 148.605 117.57 83.879 14.02 re W n<br> q<br> 1 0 0 1 148 117 cm<br> /a0 gs /x8 Do<br> Q<br> Q</div> <div class="moz-cite-prefix">[...]</div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix">The ExtGState definitions says:</div> <div class="moz-cite-prefix">/a0 <<<br> /CA 1<br> /ca 1<br> >></div> <div class="moz-cite-prefix">/b14 <<<br> /BM /Multiply<br> >></div> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix">Adding /b14 gs to drawing of the second XObject (i.e. /x8) fixes the output.</div> <div class="moz-cite-prefix"><br> </div> Maybe someone with more knowledge about cairo's pdf surface and/or pdftocairo can help here? <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix"> Tobias<br> </div> <br> <div class="moz-cite-prefix"><br> </div> <div class="moz-cite-prefix">On 03/11/2022 13:47, Beckmann Urs (ID) wrote:<br> </div> <blockquote type="cite" cite="mid:f46755f73b634df9bfd19577f0ae8b1e@id.ethz.ch"> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <meta name="Generator" content="Microsoft Word 15 (filtered medium)"> <style>@font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4;}@font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4;}p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0in; font-size:11.0pt; font-family:"Calibri",sans-serif; mso-fareast-language:EN-US;}span.EmailStyle17 {mso-style-type:personal-compose; font-family:"Calibri",sans-serif; color:windowtext;}.MsoChpDefault {mso-style-type:export-only; font-family:"Calibri",sans-serif; mso-fareast-language:EN-US;}div.WordSection1 {page:WordSection1;}</style> <div class="WordSection1"> <p class="MsoNormal"><span lang="EN-US">Dear Cairo developers<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span lang="EN-US">The attached pdf small-sample-with-comments.pdf gives incorrect output from pdftocairo -pdf.<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US">The yellow stripe covers the text “Virtual Mechanics”, instead of being transparent. Text “small” instead remains correctly not covered after pdftocairo -pdf.<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US">pdftocairo -png and pdftocairo -ps give correct results. It looks like the problem comes from cairo pdf output engine.<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US">Tested with cairo-version 1.17.4<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span lang="EN-US">Kind regards<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US">Urs<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><o:p> </o:p></p> </div> </blockquote> <p><br> </p> </blockquote> <p><br> </p> </body> </html>