text: Fix getCharBoundaries() for 0-width characters

core/src/avm2/globals/flash/text/text_field.rs

@@ -1784,6 +1784,10 @@ pub fn get_char_boundaries<'gc>(
         return Ok(Value::Null);
     };
 
+    if bounds.width() == swf::Twips::ZERO {
+        return Ok(Value::Null);
+    }
+
     let rect = activation
         .avm2()
         .classes()

core/src/font.rs

@@ -592,6 +592,9 @@ impl<'gc> Font<'gc> {
     /// of transforms and glyphs which will be consumed by the `glyph_func`
     /// closure. This corresponds to the series of drawing operations necessary
     /// to render the text on a single horizontal line.
+    ///
+    /// It's guaranteed that this function will iterate over all characters
+    /// from the text, irrespectively of whether they have a glyph or not.
     pub fn evaluate<FGlyph>(
         &self,
         text: &WStr, // TODO: take an `IntoIterator<Item=char>`, to not depend on string representation?
@@ -606,6 +609,9 @@ impl<'gc> Font<'gc> {
 
         transform.matrix.a = scale;
         transform.matrix.d = scale;
+
+        // TODO [KJ] I'm not sure whether we should iterate over characters here or over code units.
+        //   I suspect Flash Player does not support full UTF-16 when displaying and laying out text.
         let mut char_indices = text.char_indices().peekable();
         let has_kerning_info = self.has_kerning_info();
         let mut x = Twips::ZERO;
@@ -637,6 +643,10 @@ impl<'gc> Font<'gc> {
                 // Step horizontally.
                 transform.matrix.tx += twips_advance;
                 x += twips_advance;
+            } else {
+                // No glyph, zero advance.  This makes it possible to use this method for purposes
+                // other than rendering the font, e.g. measurement, iterating over characters.
+                glyph_func(pos, &transform, &Glyph::empty(c), Twips::ZERO, x);
             }
         }
     }
@@ -818,6 +828,16 @@ pub struct Glyph {
 }
 
 impl Glyph {
+    /// Returns an empty glyph with zero advance.
+    pub fn empty(character: char) -> Self {
+        Self {
+            shape_handle: Default::default(),
+            shape: GlyphShape::None,
+            advance: Twips::ZERO,
+            character,
+        }
+    }
+
     pub fn shape_handle(&self, renderer: &mut dyn RenderBackend) -> Option<ShapeHandle> {
         self.shape_handle
             .borrow_mut()

tests/tests/swfs/avm2/edittext_getcharboundaries_missing_embedded_font/Test.as

@@ -0,0 +1,41 @@
+package {
+import flash.display.Sprite;
+import flash.text.TextField;
+import flash.text.TextFormat;
+
+[SWF(width="400", height="400")]
+public class Test extends Sprite {
+    private var text:TextField;
+
+    public function Test() {
+        stage.scaleMode = "noScale";
+        text = new TextField();
+        text.border = true;
+        text.x = 10;
+        text.y = 10;
+        text.width = 380;
+        text.height = 380;
+        text.multiline = true;
+        text.embedFonts = true;
+        addChild(text);
+
+        testHtml("<font face='Unknown Font'>x y</font>");
+    }
+
+    private function testHtml(htmlText:String):void {
+        text.htmlText = htmlText;
+        trace("Text: " + htmlText.replace(/[\r\n]/g, "\\n"));
+
+        testAt(-5);
+        testAt(-1);
+        for (var i = 0; i <= text.text.length; ++i) {
+            testAt(i);
+        }
+    }
+
+    private function testAt(charIndex:int):void {
+        var bounds = text.getCharBoundaries(charIndex);
+        trace("  text.getCharBoundaries(" + charIndex + ") = " + bounds);
+    }
+}
+}

tests/tests/swfs/avm2/edittext_getcharboundaries_missing_embedded_font/output.txt

@@ -0,0 +1,7 @@
+Text: <font face='Unknown Font'>x y</font>
+  text.getCharBoundaries(-5) = null
+  text.getCharBoundaries(-1) = null
+  text.getCharBoundaries(0) = null
+  text.getCharBoundaries(1) = null
+  text.getCharBoundaries(2) = null
+  text.getCharBoundaries(3) = null

tests/tests/swfs/avm2/edittext_getcharboundaries_missing_embedded_font/test.toml

@@ -0,0 +1,4 @@
+num_ticks = 1
+
+# Currently Ruffle falls back to device font on missing embedded font.
+known_failure = true

tests/tests/swfs/avm2/edittext_getcharboundaries_missing_glyphs/Test.as

@@ -0,0 +1,49 @@
+package {
+import flash.display.Sprite;
+import flash.text.TextField;
+import flash.text.TextFormat;
+
+[SWF(width="400", height="400")]
+public class Test extends Sprite {
+    [Embed(source="TestFont.ttf", fontName="TestFont", embedAsCFF="false", unicodeRange="U+0061-U+0066")]
+    private var TestFont:Class;
+
+    private var text:TextField;
+
+    public function Test() {
+        stage.scaleMode = "noScale";
+        text = new TextField();
+        text.border = true;
+        text.x = 10;
+        text.y = 10;
+        text.width = 380;
+        text.height = 380;
+        text.multiline = true;
+        text.embedFonts = true;
+        addChild(text);
+
+        testHtml("<font face='TestFont'>x y</font>");
+        testHtml("<font face='TestFont'>abcd ab</font>");
+
+        text.wordWrap = true;
+        testHtml("<p align='justify'><font size='30' face='TestFont'>ab ab abababababa</font></p>");
+        testHtml("<p align='justify'><font size='30' face='TestFont'>ab ab abababababab</font></p>");
+    }
+
+    private function testHtml(htmlText:String):void {
+        text.htmlText = htmlText;
+        trace("Text: " + htmlText.replace(/[\r\n]/g, "\\n"));
+
+        testAt(-5);
+        testAt(-1);
+        for (var i = 0; i <= text.text.length; ++i) {
+            testAt(i);
+        }
+    }
+
+    private function testAt(charIndex:int):void {
+        var bounds = text.getCharBoundaries(charIndex);
+        trace("  text.getCharBoundaries(" + charIndex + ") = " + bounds);
+    }
+}
+}

tests/tests/swfs/avm2/edittext_getcharboundaries_missing_glyphs/output.txt

@@ -0,0 +1,63 @@
+Text: <font face='TestFont'>x y</font>
+  text.getCharBoundaries(-5) = null
+  text.getCharBoundaries(-1) = null
+  text.getCharBoundaries(0) = null
+  text.getCharBoundaries(1) = null
+  text.getCharBoundaries(2) = null
+  text.getCharBoundaries(3) = null
+Text: <font face='TestFont'>abcd ab</font>
+  text.getCharBoundaries(-5) = null
+  text.getCharBoundaries(-1) = null
+  text.getCharBoundaries(0) = (x=2, y=2, w=9.6, h=12)
+  text.getCharBoundaries(1) = (x=11.6, y=2, w=9.6, h=12)
+  text.getCharBoundaries(2) = null
+  text.getCharBoundaries(3) = null
+  text.getCharBoundaries(4) = null
+  text.getCharBoundaries(5) = (x=21.2, y=2, w=9.6, h=12)
+  text.getCharBoundaries(6) = (x=30.8, y=2, w=9.6, h=12)
+  text.getCharBoundaries(7) = null
+Text: <p align='justify'><font size='30' face='TestFont'>ab ab abababababa</font></p>
+  text.getCharBoundaries(-5) = null
+  text.getCharBoundaries(-1) = null
+  text.getCharBoundaries(0) = (x=2, y=2, w=24, h=30)
+  text.getCharBoundaries(1) = (x=26, y=2, w=24, h=30)
+  text.getCharBoundaries(2) = null
+  text.getCharBoundaries(3) = (x=50, y=2, w=24, h=30)
+  text.getCharBoundaries(4) = (x=74, y=2, w=24, h=30)
+  text.getCharBoundaries(5) = null
+  text.getCharBoundaries(6) = (x=98, y=2, w=24, h=30)
+  text.getCharBoundaries(7) = (x=122, y=2, w=24, h=30)
+  text.getCharBoundaries(8) = (x=146, y=2, w=24, h=30)
+  text.getCharBoundaries(9) = (x=170, y=2, w=24, h=30)
+  text.getCharBoundaries(10) = (x=194, y=2, w=24, h=30)
+  text.getCharBoundaries(11) = (x=218, y=2, w=24, h=30)
+  text.getCharBoundaries(12) = (x=242, y=2, w=24, h=30)
+  text.getCharBoundaries(13) = (x=266, y=2, w=24, h=30)
+  text.getCharBoundaries(14) = (x=290, y=2, w=24, h=30)
+  text.getCharBoundaries(15) = (x=314, y=2, w=24, h=30)
+  text.getCharBoundaries(16) = (x=338, y=2, w=24, h=30)
+  text.getCharBoundaries(17) = null
+  text.getCharBoundaries(18) = null
+Text: <p align='justify'><font size='30' face='TestFont'>ab ab abababababab</font></p>
+  text.getCharBoundaries(-5) = null
+  text.getCharBoundaries(-1) = null
+  text.getCharBoundaries(0) = (x=2, y=2, w=24, h=30)
+  text.getCharBoundaries(1) = (x=26, y=2, w=24, h=30)
+  text.getCharBoundaries(2) = (x=50, y=2, w=280, h=30)
+  text.getCharBoundaries(3) = (x=330, y=2, w=24, h=30)
+  text.getCharBoundaries(4) = (x=354, y=2, w=24, h=30)
+  text.getCharBoundaries(5) = null
+  text.getCharBoundaries(6) = (x=2, y=32, w=24, h=30)
+  text.getCharBoundaries(7) = (x=26, y=32, w=24, h=30)
+  text.getCharBoundaries(8) = (x=50, y=32, w=24, h=30)
+  text.getCharBoundaries(9) = (x=74, y=32, w=24, h=30)
+  text.getCharBoundaries(10) = (x=98, y=32, w=24, h=30)
+  text.getCharBoundaries(11) = (x=122, y=32, w=24, h=30)
+  text.getCharBoundaries(12) = (x=146, y=32, w=24, h=30)
+  text.getCharBoundaries(13) = (x=170, y=32, w=24, h=30)
+  text.getCharBoundaries(14) = (x=194, y=32, w=24, h=30)
+  text.getCharBoundaries(15) = (x=218, y=32, w=24, h=30)
+  text.getCharBoundaries(16) = (x=242, y=32, w=24, h=30)
+  text.getCharBoundaries(17) = (x=266, y=32, w=24, h=30)
+  text.getCharBoundaries(18) = null
+  text.getCharBoundaries(19) = null

tests/tests/swfs/avm2/edittext_getcharboundaries_missing_glyphs/test.toml

@@ -0,0 +1 @@
+num_ticks = 1