Code editor fix for long lines.

modules/juce_gui_extra/code_editor/juce_CodeEditorComponent.cpp

@@ -41,7 +41,8 @@ public:
 
         if (tokeniser == nullptr)
         {
-            newTokens.add (SyntaxToken (document.getLine (lineNum), -1));
+            const String line (document.getLine (lineNum));
+            addToken (newTokens, line, line.length(), -1);
         }
         else if (lineNum < document.getNumLines())
         {
@@ -81,22 +82,29 @@ public:
     }
 
     void draw (CodeEditorComponent& owner, Graphics& g, const Font& font,
-               float x, const float rightEdge, const int y, const int baselineOffset, const int lineHeight,
+               const float leftClip, const float rightClip,
+               const float xOffset, const int y, const int baselineOffset,
+               const int lineHeight, const float charWidth,
                const Colour& highlightColour) const
     {
         if (highlightColumnStart < highlightColumnEnd)
         {
             g.setColour (highlightColour);
-            g.fillRect (roundToInt (x + highlightColumnStart * owner.getCharWidth()), y,
+            g.fillRect (roundToInt (xOffset + highlightColumnStart * owner.getCharWidth()), y,
                         roundToInt ((highlightColumnEnd - highlightColumnStart) * owner.getCharWidth()), lineHeight);
         }
 
         const float baselineY = (float) (y + baselineOffset);
         Colour lastColour (0x00000001);
         GlyphArrangement ga;
+        int column = 0;
 
         for (int i = 0; i < tokens.size(); ++i)
         {
+            const float tokenX = xOffset + column * charWidth;
+            if (tokenX > rightClip)
+                break;
+
             SyntaxToken& token = tokens.getReference(i);
 
             const Colour newColour (owner.getColourForTokenType (token.tokenType));
@@ -109,18 +117,11 @@ public:
                 g.setColour (newColour);
             }
 
-            ga.addCurtailedLineOfText (font, token.text, x, baselineY, rightEdge - x, false);
-
-            if (i < tokens.size() - 1)
-            {
-                if (token.width < 0)
-                    token.width = font.getStringWidthFloat (token.text);
-
-                x += token.width;
+            column += token.length;
 
-                if (x > rightEdge)
-                    break;
-            }
+            if (xOffset + column * charWidth >= leftClip)
+                ga.addCurtailedLineOfText (font, token.text, tokenX, baselineY,
+                                           (rightClip - tokenX) + charWidth, false);
         }
 
         ga.draw (g);
@@ -129,19 +130,21 @@ public:
 private:
     struct SyntaxToken
     {
-        SyntaxToken (const String& t, const int type) noexcept
-            : text (t), tokenType (type), width (-1.0f)
+        SyntaxToken (const String& t, const int len, const int type) noexcept
+            : text (t), length (len), tokenType (type)
         {
         }
 
         bool operator== (const SyntaxToken& other) const noexcept
         {
-            return tokenType == other.tokenType && text == other.text;
+            return tokenType == other.tokenType
+                    && length == other.length
+                    && text == other.text;
         }
 
         String text;
+        int length;
         int tokenType;
-        float width;
     };
 
     Array <SyntaxToken> tokens;
@@ -169,8 +172,9 @@ private:
             if (tokenEnd > 0)
             {
                 tokenStart -= startPosition;
-                newTokens.add (SyntaxToken (lineText.substring (jmax (0, tokenStart), tokenEnd),
-                                            tokenType));
+                const int start = jmax (0, tokenStart);
+                addToken (newTokens, lineText.substring (start, tokenEnd),
+                          tokenEnd - start, tokenType);
 
                 if (tokenEnd >= lineLength)
                     break;
@@ -219,6 +223,21 @@ private:
 
         return col;
     }
+
+    static void addToken (Array<SyntaxToken>& dest, const String& text,
+                          const int length, const int type)
+    {
+        if (length > 1000)
+        {
+            // subdivide very long tokens to avoid unwieldy glyph sequences
+            addToken (dest, text.substring (0, length / 2), length / 2, type);
+            addToken (dest, text.substring (length / 2), length - length / 2, type);
+        }
+        else
+        {
+            dest.add (SyntaxToken (text, length, type));
+        }
+    }
 };
 
 namespace CodeEditorHelpers
@@ -451,11 +470,13 @@ void CodeEditorComponent::paint (Graphics& g)
     const int firstLineToDraw = jmax (0, clip.getY() / lineHeight);
     const int lastLineToDraw = jmin (lines.size(), clip.getBottom() / lineHeight + 1);
     const float x = (float) (gutter - xOffset * charWidth);
-    const float rightEdge = (float) getWidth();
+    const float leftClip  = (float) clip.getX();
+    const float rightClip = (float) clip.getRight();
 
     for (int i = firstLineToDraw; i < lastLineToDraw; ++i)
-        lines.getUnchecked(i)->draw (*this, g, font, x, rightEdge, lineHeight * i,
-                                     baselineOffset, lineHeight, highlightColour);
+        lines.getUnchecked(i)->draw (*this, g, font, leftClip, rightClip,
+                                     x, lineHeight * i, baselineOffset,
+                                     lineHeight, charWidth, highlightColour);
 }
 
 void CodeEditorComponent::setScrollbarThickness (const int thickness)