C++, font renderer: add support for explicit newlines

cpp/src/monoformat_fontreader.hpp

@@ -527,9 +527,10 @@ public:
                 continue;
             }
 
-            // FIXME: newline support
             if (cp == '\n') {
-                cp = ' ';
+                advance.x = 0;
+                advance.y += m_font.lineHeight();
+                continue;
             }
 
             auto dims = renderGlyph(cp, position + advance, m_font, display, fontColor, bgColor);
@@ -557,10 +558,11 @@ public:
                 continue;
             }
 
-            // FIXME: newline support
-            // also FIXME: call ensureAdvance when handling newline
             if (cp == '\n') {
-                cp = ' ';
+                ensureAdvance(boundingBox, advance);
+                advance.x = 0;
+                advance.y += m_font.lineHeight();
+                continue;
             }
 
             auto dims = computeGlyphDimensions(cp, position + advance, m_font);
@@ -627,15 +629,14 @@ private:
             return std::nullopt;
         }
 
-        // FIXME: once we support multi-line also handle y component
-
         auto bottomRight = a->getBottomRight();
         if ((bottomRight.x + 1) < advance.x) {
             bottomRight.x = advance.x - 1;
-            return Rectangle::fromCorners(a->topLeft, bottomRight);
-        } else {
-            return a;
         }
+        if ((bottomRight.y + 1) < advance.y) {
+            bottomRight.y = advance.y - 1;
+        }
+        return Rectangle::fromCorners(a->topLeft, bottomRight);
     }
 
     template<typename Display>