Fix text renderer (#131)

fix glyph cache layout

The row height was never summed to itself so from the third row
onwards would appear in the same height as the second row

The code is therefore simplied to always track the `max_height`
attained by any given glyph

Fixes #112

crates/yakui-widgets/src/text_renderer.rs

@@ -28,7 +28,7 @@ pub struct GlyphCache {
     pub texture_size: UVec2,
     glyphs: HashMap<GlyphRasterConfig, URect>,
     next_pos: UVec2,
-    row_height: u32,
+    max_height: u32,
 }
 
 impl GlyphCache {
@@ -60,14 +60,12 @@ impl GlyphCache {
 
             let glyph_max = self.next_pos + glyph_size;
             let pos = if glyph_max.x < self.texture_size.x {
-                let pos = self.next_pos;
-                self.row_height = self.row_height.max(glyph_size.y + 1);
-                pos
+                self.next_pos
             } else {
-                let pos = UVec2::new(0, self.row_height);
-                self.row_height = 0;
-                pos
+                UVec2::new(0, self.max_height)
             };
+
+            self.max_height = self.max_height.max(pos.y + glyph_size.y + 1);
             self.next_pos = pos + UVec2::new(glyph_size.x + 1, 0);
 
             let size = texture.size();
@@ -111,7 +109,7 @@ impl TextGlobalState {
             texture: None,
             glyphs: HashMap::new(),
             next_pos: UVec2::ONE,
-            row_height: 0,
+            max_height: 0,
 
             // Not initializing to zero to avoid divide by zero issues if we do
             // intialize the texture incorrectly.