4.0.1 fix for custom line-height on font

pixie.nimble

@@ -1,4 +1,4 @@
-version     = "4.0.0"
+version     = "4.0.1"
 author      = "Andre von Houck and Ryan Oldenburg"
 description = "Full-featured 2d graphics library for Nim."
 license     = "MIT"

src/pixie/fonts.nim

@@ -82,6 +82,7 @@ proc lineGap*(typeface: Typeface): float32 {.raises: [].} =
 
 proc lineHeight*(typeface: Typeface): float32 {.inline, raises: [].} =
   ## The default line height in font units.
+  # The descent is negative number, so this is really ascent + descent + lineGap.
   typeface.ascent - typeface.descent + typeface.lineGap
 
 proc underlinePosition(typeface: Typeface): float32 =
@@ -186,6 +187,18 @@ proc defaultLineHeight*(font: Font): float32 {.inline, raises: [].} =
     font.typeface.ascent - font.typeface.descent + font.typeface.lineGap
   round(fontUnits * font.scale)
 
+proc lineGap(font: Font): float32 =
+  ## The line gap in font units for the current font size and line-height.
+  let lineHeight =
+    if font.lineHeight >= 0:
+      font.lineHeight
+    else:
+      font.defaultLineHeight
+  if lineHeight == font.defaultLineHeight:
+    font.typeface.lineGap
+  else:
+    (lineHeight / font.scale) - font.typeface.ascent + font.typeface.descent
+
 proc paint*(font: Font): Paint {.inline, raises: [].} =
   font.paints[0]
 
@@ -356,20 +369,10 @@ proc typeset*(
         for spanIndex, (start, stop) in result.spans:
           let
             font = result.fonts[spanIndex]
-            lineHeight =
-              if font.lineHeight >= 0:
-                font.lineHeight
-              else:
-                font.defaultLineHeight
-          var fontUnitInitialY = font.typeface.ascent + font.typeface.lineGap / 2
-          if lineHeight != font.defaultLineHeight:
-            fontUnitInitialY += (
-              (lineHeight / font.scale) - font.typeface.lineHeight
-            ) / 2
+            fontUnitInitialY = font.typeface.ascent + font.lineGap / 2
           maxInitialY = max(maxInitialY, round(fontUnitInitialY * font.scale))
-          for runeIndex in start .. stop:
-            if runeIndex == result.lines[0][1]:
-              break outer
+          if stop >= result.lines[0][1]:
+            break outer
       maxInitialY
 
     var lineHeights = newSeq[float32](result.lines.len)
@@ -385,6 +388,8 @@ proc typeset*(
               font.defaultLineHeight
         lineHeights[line] = max(lineHeights[line], fontLineHeight)
         for runeIndex in start .. stop:
+          # This span could be many lines. This check can be made faster by
+          # hopping based on line endings instead of checking each index.
           if line + 1 < result.lines.len and
             runeIndex == result.lines[line + 1][0]:
             inc line
@@ -401,8 +406,8 @@ proc typeset*(
         let
           font = result.fonts[spanIndex]
           lineHeight =
-            if font.lineheight >= 0:
-              font.lineheight
+            if font.lineHeight >= 0:
+              font.lineHeight
             else:
               font.defaultLineHeight
         for runeIndex in start .. stop:
@@ -411,8 +416,8 @@ proc typeset*(
             inc line
             baseline += lineHeights[line]
           result.positions[runeIndex].y = baseline
-          result.selectionRects[runeIndex].y =
-            baseline - round(font.typeface.ascent * font.scale)
+          result.selectionRects[runeIndex].y = baseline -
+            round((font.typeface.ascent + font.lineGap / 2) * font.scale)
           result.selectionRects[runeIndex].h = lineHeight
 
     if vAlign != TopAlign:

tests/test_fonts.nim

@@ -1101,3 +1101,61 @@ block:
   image.fillText(font, "This[]Advance!")
 
   doDiff(image, "tofu_advance")
+
+block:
+  let image = newImage(200, 200)
+  image.fill(color(1, 1, 1, 1))
+
+  let paint = newPaint(SolidPaint)
+  paint.color = color(1, 0, 0, 1)
+
+  let ctx = newContext(image)
+  ctx.lineWidth = 1
+  ctx.strokeStyle = paint
+  ctx.strokeRect(0, 60, 200, 80)
+
+  let text = "AbCd\naBcD"
+
+  let font = pixie.read_font("tests/fonts/Inter-Bold.ttf")
+  font.size = 40
+  font.line_height = 27
+
+  let arrangement1 = font.typeset(
+    text,
+    vec2(200, 80),
+    CenterAlign,
+    TopAlign
+  )
+
+  # let p1 = newPath()
+  # p1.rect(arrangement1.selectionRects[0])
+  # image.fillpath(p1, rgba(196, 196, 196, 255), translate(vec2(0, 266)))
+
+  font.paint.color = color(1, 0, 0, 1)
+  image.fillText(arrangement1, translate(vec2(0, 60)))
+
+  let arrangement2 = font.typeset(
+    text,
+    vec2(200, 80),
+    CenterAlign,
+    MiddleAlign
+  )
+
+  # let p2 = newPath()
+  # p2.rect(arrangement2.selectionRects[0])
+  # image.fillpath(p2, rgba(196, 196, 196, 255), translate(vec2(0, 266)))
+
+  font.paint.color = color(0, 1, 0, 1)
+  image.fillText(arrangement2, translate(vec2(0, 60)))
+
+  font.paint.color = color(0, 0, 1, 1)
+  image.fillText(
+      font,
+      text,
+      bounds = vec2(200, 80),
+      hAlign = CenterAlign,
+      vAlign = BottomAlign,
+      transform = translate(vec2(0, 60))
+  )
+
+  doDiff(image, "customlineheight")

tests/test_paints.nim

@@ -14,7 +14,7 @@ block:
     heartShape,
     rgba(255, 0, 0, 255)
   )
-  image.writeFile("tests/paths/SolidPaint.png")
+  image.writeFile("tests/paths/paintSolid.png")
 
 block:
   let paint = newPaint(ImagePaint)
@@ -23,7 +23,7 @@ block:
 
   let image = newImage(100, 100)
   image.fillPath(heartShape, paint)
-  image.writeFile("tests/paths/ImagePaint.png")
+  image.writeFile("tests/paths/paintImage.png")
 
 block:
   let paint = newPaint(ImagePaint)
@@ -42,7 +42,7 @@ block:
 
   let image = newImage(100, 100)
   image.fillPath(heartShape, paint)
-  image.writeFile("tests/paths/TiledImagePaint.png")
+  image.writeFile("tests/paths/paintImageTiled.png")
 
 block:
   let paint = newPaint(TiledImagePaint)