Show tabs in pre elements

Display tab characters as 8 spaces for pre and other elements that don't compress whitespace.
servo · Apr 3, 2015 · 29852bb · 29852bb · bors-servo · Apr 3, 2015
1 parent 225d7d2
commit 29852bb
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Showing 4 changed files with 19 additions and 0 deletions.
diff --git a/components/gfx/text/shaping/harfbuzz.rs b/components/gfx/text/shaping/harfbuzz.rs
@@ -521,6 +521,9 @@ impl Shaper {
         // We elect to only space the two required code points.
         if character == ' ' || character == '\u{a0}' {
             advance = advance + options.word_spacing
+        } else if character == '\t' {
+            let tab_size = 8f64;
+            advance = Au::from_frac_px(tab_size * glyph_space_advance(self.font_and_shaping_options.font));
         }
 
         advance
@@ -563,6 +566,19 @@ extern fn glyph_h_advance_func(_: *mut hb_font_t,
     }
 }
 
+fn glyph_space_advance(font: *mut Font) -> f64 {
+    let space_unicode = ' ';
+    let space_glyph: hb_codepoint_t;
+    match unsafe {(*font).glyph_index(space_unicode)} {
+        Some(g) => {
+            space_glyph = g as hb_codepoint_t;
+        }
+        None => panic!("No space info")
+    }
+    let space_advance = unsafe {(*font).glyph_h_advance(space_glyph as GlyphId)};
+    space_advance
+}
+
 extern fn glyph_h_kerning_func(_: *mut hb_font_t,
                                font_data: *mut c_void,
                                first_glyph: hb_codepoint_t,

diff --git a/tests/ref/basic.list b/tests/ref/basic.list
@@ -245,6 +245,7 @@ experimental != overconstrained_block.html overconstrained_block_ref.html
 == position_relative_a.html position_relative_b.html
 == position_relative_top_percentage_a.html position_relative_top_percentage_b.html
 == pre_ignorable_whitespace_a.html pre_ignorable_whitespace_ref.html
+== pre_with_tab.html pre_with_tab_ref.html
 == pseudo_element_a.html pseudo_element_b.html
 == pseudo_inherit.html pseudo_inherit_ref.html
 == quotes_simple_a.html quotes_simple_ref.html

diff --git a/tests/ref/pre_with_tab.html b/tests/ref/pre_with_tab.html
@@ -0,0 +1 @@
+<html><body><pre>	tab</pre></body></html>
diff --git a/tests/ref/pre_with_tab_ref.html b/tests/ref/pre_with_tab_ref.html
@@ -0,0 +1 @@
+<html><body><pre>        tab</pre></body></html>