Add support for variable fonts

.typos.toml

@@ -16,6 +16,7 @@ SVGinOT = "SVGinOT"
 
 # Match Inside a Word - Case Insensitive
 [default.extend-words]
+wdth = "wdth"
 
 [files]
 # Include .github, .cargo, etc.

crates/resvg/tests/fonts/README.md

@@ -14,4 +14,9 @@ Noto COLOR Emoji (COLRv1)
 3. Run `fonttools ttx NotoColorEmojiCOLR.subset.ttf`
 4. Go to the <name> section and rename all instances of "Noto Color Emoji" to "Noto Color Emoji COLR" (so that
 we can distinguish them from CBDT in tests).
-5. Run `fonttools ttx -f NotoColorEmojiCOLR.subset.ttx`
+5. Run `fonttools ttx -f NotoColorEmojiCOLR.subset.ttx`
+
+Roboto Flex (Variable Font)
+1. Download: https://github.com/googlefonts/roboto-flex/raw/main/fonts/RobotoFlex%5BGRAD%2CXOPQ%2CXTRA%2CYOPQ%2CYTAS%2CYTDE%2CYTFI%2CYTLC%2CYTUC%2Copsz%2Cslnt%2Cwdth%2Cwght%5D.ttf
+2. Run `pyftsubset RobotoFlex*.ttf --unicodes="U+0020-007E" --layout-features='*' --drop-tables= --output-file=RobotoFlex.subset.ttf`
+3. Copy OFL license from https://github.com/googlefonts/roboto-flex/blob/main/OFL.txt

crates/resvg/tests/fonts/RobotoFlex-LICENSE-OFL.txt

@@ -0,0 +1,93 @@
+Copyright 2011 The Roboto Flex Project Authors (https://github.com/googlefonts/roboto-flex)
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

crates/resvg/tests/integration/render.rs

@@ -1457,6 +1457,20 @@ use crate::render;
 #[test] fn text_font_style_oblique() { assert_eq!(render("tests/text/font-style/oblique"), 0); }
 #[test] fn text_font_variant_inherit() { assert_eq!(render("tests/text/font-variant/inherit"), 0); }
 #[test] fn text_font_variant_small_caps() { assert_eq!(render("tests/text/font-variant/small-caps"), 0); }
+#[test] fn text_font_variation_settings_all_axes_combined() { assert_eq!(render("tests/text/font-variation-settings/all-axes-combined"), 0); }
+#[test] fn text_font_variation_settings_auto_font_stretch_condensed() { assert_eq!(render("tests/text/font-variation-settings/auto-font-stretch-condensed"), 0); }
+#[test] fn text_font_variation_settings_auto_font_style_oblique() { assert_eq!(render("tests/text/font-variation-settings/auto-font-style-oblique"), 0); }
+#[test] fn text_font_variation_settings_auto_font_weight_700() { assert_eq!(render("tests/text/font-variation-settings/auto-font-weight-700"), 0); }
+#[test] fn text_font_variation_settings_explicit_overrides_auto() { assert_eq!(render("tests/text/font-variation-settings/explicit-overrides-auto"), 0); }
+#[test] fn text_font_variation_settings_grad_negative() { assert_eq!(render("tests/text/font-variation-settings/grad-negative"), 0); }
+#[test] fn text_font_variation_settings_multiple_axes() { assert_eq!(render("tests/text/font-variation-settings/multiple-axes"), 0); }
+#[test] fn text_font_variation_settings_opsz_144() { assert_eq!(render("tests/text/font-variation-settings/opsz-144"), 0); }
+#[test] fn text_font_variation_settings_slnt_negative() { assert_eq!(render("tests/text/font-variation-settings/slnt-negative"), 0); }
+#[test] fn text_font_variation_settings_wdth_151() { assert_eq!(render("tests/text/font-variation-settings/wdth-151"), 0); }
+#[test] fn text_font_variation_settings_wdth_25() { assert_eq!(render("tests/text/font-variation-settings/wdth-25"), 0); }
+#[test] fn text_font_variation_settings_wght_100() { assert_eq!(render("tests/text/font-variation-settings/wght-100"), 0); }
+#[test] fn text_font_variation_settings_wght_700() { assert_eq!(render("tests/text/font-variation-settings/wght-700"), 0); }
+#[test] fn text_font_variation_settings_xtra_extreme() { assert_eq!(render("tests/text/font-variation-settings/xtra-extreme"), 0); }
 #[test] fn text_font_weight_650() { assert_eq!(render("tests/text/font-weight/650"), 0); }
 #[test] fn text_font_weight_700() { assert_eq!(render("tests/text/font-weight/700"), 0); }
 #[test] fn text_font_weight_bold() { assert_eq!(render("tests/text/font-weight/bold"), 0); }

crates/usvg/Cargo.toml

@@ -38,6 +38,9 @@ siphasher = "1.0" # perfect hash implementation
 # text
 fontdb = { version = "0.23.0", default-features = false, optional = true }
 rustybuzz = { version = "0.20.1", optional = true }
+# Note: ttf-parser is re-exported from rustybuzz, but we need gvar-alloc for variable fonts
+# with many variation axes (like Roboto Flex which has 13 axes)
+ttf-parser = { version = "0.25.1", features = ["gvar-alloc"], optional = true }
 unicode-bidi = { version = "0.3", optional = true }
 unicode-script = { version = "0.5", optional = true }
 unicode-vo = { version = "0.1", optional = true }
@@ -49,7 +52,7 @@ once_cell = "1.5"
 default = ["text", "system-fonts", "memmap-fonts"]
 # Enables text-to-path conversion support.
 # Adds around 400KiB to your binary.
-text = ["fontdb", "rustybuzz", "unicode-bidi", "unicode-script", "unicode-vo"]
+text = ["fontdb", "rustybuzz", "ttf-parser", "unicode-bidi", "unicode-script", "unicode-vo"]
 # Enables system fonts loading.
 system-fonts = ["fontdb/fs", "fontdb/fontconfig"]
 # Enables font files memmaping for faster loading.

crates/usvg/codegen/attributes.txt

@@ -40,6 +40,7 @@ font
 font-family
 font-feature-settings
 font-kerning
+font-optical-sizing
 font-size
 font-size-adjust
 font-stretch
@@ -51,6 +52,7 @@ font-variant-east-asian
 font-variant-ligatures
 font-variant-numeric
 font-variant-position
+font-variation-settings
 font-weight
 fr
 fx

crates/usvg/src/parser/svgtree/mod.rs

@@ -710,12 +710,14 @@ impl AId {
                 | AId::FloodOpacity
                 | AId::FontFamily
                 | AId::FontKerning // technically not presentation
+                | AId::FontOpticalSizing // technically not presentation
                 | AId::FontSize
                 | AId::FontSizeAdjust
                 | AId::FontStretch
                 | AId::FontStyle
                 | AId::FontVariant
                 | AId::FontWeight
+                | AId::FontVariationSettings
                 | AId::GlyphOrientationHorizontal
                 | AId::GlyphOrientationVertical
                 | AId::ImageRendering
@@ -786,6 +788,7 @@ impl AId {
                 | AId::FloodOpacity
                 | AId::FontFamily
                 | AId::FontKerning
+                | AId::FontOpticalSizing
                 | AId::FontSize
                 | AId::FontStretch
                 | AId::FontStyle