VFont: Use BLF for font & glyph loading #110187

Harley Acheson · 2023-07-17T03:37:03+02:00

Harley Acheson commented

2023-07-17 03:37:03 +02:00

Load VFont curves using BLF API rather than local FreeType calls.

Text objects currently use the FreeType library directly. This is a duplication of code and also means that this area cannot take advantage of the more complex features of the BLF API. This PR allows VFont to use BFont.

This means that they can use the font, face, and lookup caches and have access to all the other BLF features. This also means that the default 3D Text font can participate in the fallback stack, so new users using the default font won't be frustrated with only having 239 characters, but instead have access to more than a hundred thousand of them. And also means I can later add support for variable axes features.

And if they select something that is not in any of the fallback fonts it will load a "last resort" glyph that contains information about what is missing, not just nothing or a "tofu" square. Following shows entering characters from the Duployan and Wancho alphabets:

In order for this to work we just need three new members added to the BLF API:

BLF_display_name - the font's family and style names are required for the VFontData object
BLF_get_vfont_metrics - needed to get the vfont initial size.
BLF_character_to_curves - convert a Unicode character into curves

With BLF_get_vfont_metrics the current code is just copied from vfont so the values, and therefore the initial sizes of the text objects, remain exactly as they are now.

For BLF_character_to_curves the entirety of the existing freetype_outline_to_curves is simply moved to blf_glyph.cc, renamed blf_glyph_to_curves, along with the extensive existing comments about the process. There is a helper function blf_character_to_curves added that takes a Unicode character, gets a glyph from the font (and from the font stack if not found), calls blf_glyph_to_curves and returns the scaled advance.

There are some small changes in blf_glyph.cc mostly to handle getting outlines without rasterizing, and without needing to use GlyphCacheBLF at all. Otherwise there isn't too much to this.

Load VFont curves using BLF API rather than local FreeType calls. --- Text objects currently use the FreeType library directly. This is a duplication of code and also means that this area cannot take advantage of the more complex features of the BLF API. This PR allows VFont to use BFont. This means that they can use the font, face, and lookup caches and have access to all the other BLF features. This also means that the default 3D Text font can participate in the fallback stack, so new users using the default font won't be frustrated with only having 239 characters, but instead have access to more than a hundred thousand of them. And also means I can later add support for variable axes features. ![image](/attachments/19670109-e532-458f-a482-312aa17a51b8) And if they select something that is not in any of the fallback fonts it will load a "last resort" glyph that contains information about what is missing, not just nothing or a "tofu" square. Following shows entering characters from the Duployan and Wancho alphabets: ![image](/attachments/4942f24e-e19a-44ce-b59b-ec7f0171cf81) In order for this to work we just need three new members added to the BLF API: * BLF_display_name - the font's family and style names are required for the VFontData object * BLF_get_vfont_metrics - needed to get the vfont initial size. * BLF_character_to_curves - convert a Unicode character into curves With `BLF_get_vfont_metrics` the current code is just copied from vfont so the values, and therefore the initial sizes of the text objects, remain exactly as they are now. For `BLF_character_to_curves` the entirety of the existing `freetype_outline_to_curves` is simply moved to blf_glyph.cc, renamed `blf_glyph_to_curves`, along with the extensive existing comments about the process. There is a helper function `blf_character_to_curves` added that takes a Unicode character, gets a glyph from the font (and from the font stack if not found), calls `blf_glyph_to_curves` and returns the scaled advance. There are some small changes in `blf_glyph.cc` mostly to handle getting outlines without rasterizing, and without needing to use GlyphCacheBLF at all. Otherwise there isn't too much to this.

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🎉 3

Harley Acheson added this to the User Interface project 2023-07-17 03:37:53 +02:00

hamza.SMA commented

2023-07-17 22:48:38 +02:00

First-time contributor

is arabic there ?

Harley Acheson commented

2023-07-17 23:19:00 +02:00

@hamza-el-barmaki - is arabic there ?

The answer is "no" to the question that you are probably really asking, in that this does not enable LTR/RTL reordering or text shaping. But "yes" in that an Arabic font is in our fallback stack, so it is easier to get to those characters.

A common thing for new users to do is just Add / Text then try copying in emoji, symbols, or characters from their own language. Unfortunately the default font that we include for this purpose (Bfont Regular) contains very few characters so nothing comes out. Users eventually figure out that they need to select some other font in order to see anything nice.

This patch loads characters the same way the interface does. So if you type a character not in that font it will look in the fallback stack of fonts. So almost anything you can think of will come out. With Arabic they would come out backwards and bad, but at least something comes out. Enough that it might prompt you to try a precomposed string instead.

> @hamza-el-barmaki - is arabic there ? The answer is "no" to the question that you are probably really asking, in that this does **not** enable LTR/RTL reordering or text shaping. But "yes" in that an Arabic font is in our fallback stack, so it is easier to get to those characters. A common thing for new users to do is just Add / Text then try copying in emoji, symbols, or characters from their own language. Unfortunately the default font that we include for this purpose (Bfont Regular) contains very few characters so nothing comes out. Users eventually figure out that they need to select some other font in order to see anything nice. This patch loads characters the same way the interface does. So if you type a character not in that font it will look in the fallback stack of fonts. So almost anything you can think of will come out. With Arabic they would come out backwards and bad, but at least _something_ comes out. Enough that it might prompt you to try a precomposed string instead.

👍 1

Harley Acheson changed title from ~~WIP: VFont: Use BLF for font & glyph loading~~ to VFont: Use BLF for font & glyph loading

2023-07-18 00:56:58 +02:00

Harley Acheson requested review from Campbell Barton 2023-07-18 00:57:10 +02:00

Harley Acheson force-pushed vfontblf from dd8e898d8a to 69db77403c

2023-07-31 03:50:59 +02:00

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Harley Acheson added 2 commits 2023-09-08 21:36:27 +02:00

99c288fe00 Merge branch 'main' of projects.blender.org:blender/blender into vfontblf

035026d31c Replacing NULL with nullptr

Pablo Vazquez added the

Module

User Interface

label 2023-09-13 18:03:46 +02:00

Harley Acheson added 1 commit 2023-10-05 02:08:29 +02:00

ac5b164579 Merge branch 'main' of projects.blender.org:blender/blender into vfontblf

Harley Acheson commented

2023-10-05 02:18:02 +02:00

@JulianEisel - You had asked if this uses the glyph cache, and it does not. From the vfont side it loads fonts in the same way as for bfont, but then glyph outlines are loaded directly from them, with no need for the glpyh cache. And yes, this would all allow us to do the variable and synthetic changes as seen here, but for vfont: #112454. So we could have sliders for weight, width, slant, etc.

Harley Acheson changed title from ~~VFont: Use BLF for font & glyph loading~~ to WIP: VFont: Use BLF for font & glyph loading

2023-10-06 23:20:17 +02:00

Harley Acheson commented

2023-10-06 23:32:02 +02:00

There would be no need for vfontdata_freetype.cc to have access to FT_Face or FT_GlyphSlot with a few more BLF calls (face name, some unscaled metrics), and moving freetype_outline_to_curves to BLF as something like BLF_character_as_curves(int fontid, uint character, ListBase *nurbs, const float scale)

And this would work well with BLF_character_weight, BLF_character_slant, BLF_character_width, BLF_character_spacing of #112454

Both this and #112454 would need access to unscaled metrics so the FontInfo introduced there would work for this.

There would be no need for vfontdata_freetype.cc to have access to FT_Face or FT_GlyphSlot with a few more BLF calls (face name, some unscaled metrics), and moving `freetype_outline_to_curves` to BLF as something like BLF_character_as_curves(int fontid, uint character, ListBase *nurbs, const float scale) And this would work well with BLF_character_weight, BLF_character_slant, BLF_character_width, BLF_character_spacing of #112454 Both this and #112454 would need access to unscaled metrics so the FontInfo introduced there would work for this.

Harley Acheson referenced this pull request

2023-10-07 22:14:12 +02:00

New UI Font in 4.0 Beta has inconsistent character spacing #113352

Harley Acheson referenced this pull request

2023-10-09 00:14:49 +02:00

FontBLF: Store Sizes, Styles, and Other Metrics #113432

Harley Acheson added 3 commits 2023-10-15 04:55:10 +02:00

5008897dff Merge branch 'main' of projects.blender.org:blender/blender into vfontblf

9a58bef94b Merge branch 'main' of projects.blender.org:blender/blender into vfontblf

7187b054fc Moving Curve Conversion to blf_glyph.cc

Harley Acheson added 1 commit 2023-10-15 05:10:19 +02:00

ec34c54114 Getting font name from BLF API now.