<div dir="ltr">Thanks Konstantin!<div> </div><div>Should this become a hb-uniscribe (or hb-gdi?) API?</div></div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, May 24, 2019 at 12:17 PM Konstantin Ritt <<a href="mailto:ritt.ks@gmail.com">ritt.ks@gmail.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><pre style="margin-top:0px;margin-bottom:0px">hb_blob_t *my_reference_table(hb_face_t * /*face*/, hb_tag_t tag, void *user_data)</pre> <pre style="margin-top:0px;margin-bottom:0px">{</pre> <pre style="margin-top:0px;margin-bottom:0px"> HDC hdc = (HDC)user_data;</pre> <pre style="margin-top:0px;margin-bottom:0px"> SelectObject(hdc, hfont);</pre> <pre style="margin-top:0px;margin-bottom:0px"> </pre> <pre style="margin-top:0px;margin-bottom:0px"> char *buffer = NULL;</pre> <pre style="margin-top:0px;margin-bottom:0px"> DWORD length = 0;</pre> <pre style="margin-top:0px;margin-bottom:0px"> </pre> <pre style="margin-top:0px;margin-bottom:0px"> length = GetFontData(hdc, byte_swap<DWORD>(tag), 0, buffer, length);</pre> <pre style="margin-top:0px;margin-bottom:0px"> if (length == GDI_ERROR)</pre> <pre style="margin-top:0px;margin-bottom:0px"> return hb_blob_get_empty();</pre> <pre style="margin-top:0px;margin-bottom:0px"> </pre> <pre style="margin-top:0px;margin-bottom:0px"> buffer = (char *)::malloc(length);</pre> <pre style="margin-top:0px;margin-bottom:0px"> length = GetFontData(hdc, byte_swap<DWORD>(tag), 0, buffer, length);</pre> <pre style="margin-top:0px;margin-bottom:0px"> if (length == GDI_ERROR)</pre> <pre style="margin-top:0px;margin-bottom:0px"> length = 0;</pre> <pre style="margin-top:0px;margin-bottom:0px"> </pre> <pre style="margin-top:0px;margin-bottom:0px"> return hb_blob_create((const char *)buffer, length, HB_MEMORY_MODE_READONLY, buffer, ::free);</pre> <pre style="margin-top:0px;margin-bottom:0px">}</pre> <pre style="margin-top:0px;margin-bottom:0px;color:rgb(128,128,0)"> </pre> <pre style="margin-top:0px;margin-bottom:0px">hb_face_t *my_face_create_from_hdc(HDC hdc)</pre> <pre style="margin-top:0px;margin-bottom:0px">{</pre> <pre style="margin-top:0px;margin-bottom:0px"> return hb_face_create_for_tables(my_reference_table, (void *)hdc, NULL);</pre> <pre style="margin-top:0px;margin-bottom:0px">}</pre></div><div> </div><div> </div> <div><div dir="ltr" class="gmail-m_1729726368139753960gmail_signature">Regards, Konstantin</div></div> </div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">пт, 24 мая 2019 г. в 16:39, Eli Zaretskii <<a href="mailto:eliz@gnu.org" target="_blank">eliz@gnu.org</a>>: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">> From: Ebrahim Byagowi <<a href="mailto:ebraminio@gmail.com" target="_blank">ebraminio@gmail.com</a>> > Date: Fri, 24 May 2019 20:13:43 +0430 > Cc: Harfbuzz <<a href="mailto:harfbuzz@lists.freedesktop.org" target="_blank">harfbuzz@lists.freedesktop.org</a>> > > Pardon me for the may inaccurate following answer I have to write quickly, Thanks for your help. > > Also, does HarfBuzz support TrueType Collection (TTC) files, and if so, does it want the data only for the > currently selected font or all > of the data? > > It does, if you want harfbuzz handles it for you, you should give it the full blob and set the index you like in > second argument of hb_face_create, otherwise you should handle it yourself. OK, this brings me to another question: what should I in general pass as the 2nd argument of hb_face_create? Suppose I'm using a TTF or OTF font file, should I always pass zero as the 2nd argument? What is the semantics of that argument? > > I'm now working on the HarfBuzz font driver for Emacs on Windows using GetFontData with the dwTable > argument zero, to get the entire data of the font. > > Is it DirectWrite? Have you seen the helper we have the in hb-directwrite.h and hb-uniscribe.h? They can be > very useful. I'm not using DirectWrite, nor am I using Uniscribe. My HarfBuzz is built without these two, as I understand building with these back-ends is only needed for comparison. I want to use the HarfBuzz shaper, and only it (Emacs already has support for Uniscribe). But yes, I do consult these files to figure out answers to my questions. > > does their memory need to be freed in some manner after I have the hb_font_t object, or do I have to keep > them as long as hb_font_t is in use? > > Don't free it yourself specially if in use, you can use harfbuzz destroy callback so harfbuzz can handle it for > you. Sorry, I don't think I understand: what do you mean by "harfbuzz destroy callback"? If you mean the 'destroy" argument of hb_blob_create, then AFAIU this is called only to destroy user_data, and I don't have user_data, I pass NULL as the 4th argument of hb_blob_create. And hb_face_create doesn't have any callback argument at all. I see in the few programs in util/ that both the blob and the face are destroyed as soon as hb_font_t object is created, which is why I thought I could do the same. But now you seem to say I shouldn't? For that matter, what should I use as the 'mode' argument of hb_blob_create? This page: <a href="https://harfbuzz.github.io/object-model-blobs.html" rel="noreferrer" target="_blank">https://harfbuzz.github.io/object-model-blobs.html</a> shows an example of calling hb_blob_create with 'free' (in my case, 'xfree') as the 'destroy' callback, so I guess my interpretation of that argument as being pertinent to user_data was incorrect? Still, the questions about memory management for hb_face_t and about the semantics of the hb_memory_mode_t enum values are left unanswered. > > I see that hb_blob_create, hb_face_create etc. return empty objects when they fail. But I see no "is-empty" > function or macro in the docs, did I miss something? > > Some of the objects may work with empty comparison but it is not broken face > <a href="https://github.com/harfbuzz/harfbuzz/issues/1572" rel="noreferrer" target="_blank">https://github.com/harfbuzz/harfbuzz/issues/1572</a> but something does it very accurately is > hb_face_get_glyph_count AFAIU, you are saying that if hb_face_get_glyph_count returns zero, the face is empty and shouldn't be used, is that right? > > Where do those 64.0 factors come from? > > Subpixel accuracy, harfbuzz works with integers but as subpixel accuracy needed you have to we need to do > some scaling. Scaling is not the pixels but _set_ppem and _set_ptem is (this is very inaccurate, but I hope > would be useful) Does this mean I should use the factor of 64 in my code as well? Or does that value depend on some properties of the font? > > > Or point me to the documentation where that is described, if I missed it? > > <a href="https://harfbuzz.github.io/" rel="noreferrer" target="_blank">https://harfbuzz.github.io/</a> may address some of your issues Thanks again for your help. _______________________________________________ HarfBuzz mailing list <a href="mailto:HarfBuzz@lists.freedesktop.org" target="_blank">HarfBuzz@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/harfbuzz" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/harfbuzz</a></blockquote></div> _______________________________________________ HarfBuzz mailing list <a href="mailto:HarfBuzz@lists.freedesktop.org" target="_blank">HarfBuzz@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/harfbuzz" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/harfbuzz</a></blockquote></div> <div> </div>-- <div dir="ltr" class="gmail_signature">behdad <a href="http://behdad.org/" target="_blank">http://behdad.org/</a></div>