text alignments

src/pixie/fonts.nim

@@ -139,6 +139,10 @@ proc typeset*(
       if rune.uint32 >= SP.uint32 or rune.uint32 == LF.uint32:
         result.runes.add(rune)
 
+  if result.runes.len == 0:
+    # No runes to typeset, early return
+    return
+
   result.runes.convertTextCase(textCase)
   result.positions.setLen(result.runes.len)
   result.selectionRects.setLen(result.runes.len)
@@ -197,6 +201,60 @@ proc typeset*(
       result.selectionRects[i] = rect(at.x, at.y - initialY, advance, lineHeight)
       at.x += advance
 
+  if bounds.x > 0 and hAlign != haLeft:
+    # Since horizontal alignment adjustments are different for each line,
+    # find the start and stop of each line of text.
+    var
+      lines: seq[(int, int)] # (start, stop)
+      start: int
+      prevY = result.positions[0].y
+    for i, pos in result.positions:
+      if pos.y != prevY:
+        lines.add((start, i - 1))
+        start = i
+        prevY = pos.y
+    lines.add((start, result.positions.len - 1))
+
+    for (start, stop) in lines:
+      var furthestX: float32
+      for i in countdown(stop, start):
+        if result.runes[i] != SP and result.runes[i] != LF:
+          furthestX = result.selectionRects[i].x + result.selectionRects[i].w
+          break
+
+      var xAdjustment: float32
+      case hAlign:
+        of haLeft:
+          discard
+        of haCenter:
+          xAdjustment = round((bounds.x - furthestX) / 2)
+        of haRight:
+          xAdjustment = bounds.x - furthestX
+
+      if xAdjustment != 0:
+        for i in 0 ..< result.positions.len:
+          result.positions[i].x += xAdjustment
+          result.selectionRects[i].x += xAdjustment
+
+  if bounds.y > 0:
+    let
+      finalSelectionRect = result.selectionRects[^1]
+      furthestY = finalSelectionRect.y + finalSelectionRect.h
+
+    var yAdjustment: float32
+    case vAlign:
+      of vaTop:
+        discard
+      of vaMiddle:
+        yAdjustment = round((bounds.y - furthestY) / 2)
+      of vaBottom:
+        yAdjustment = bounds.y - furthestY
+
+    if yAdjustment != 0:
+      for i in 0 ..< result.positions.len:
+        result.positions[i].y += yAdjustment
+        result.selectionRects[i].y += yAdjustment
+
 iterator paths*(arrangement: Arrangement): Path =
   for i in 0 ..< arrangement.runes.len:
     if arrangement.runes[i].uint32 > SP.uint32: # Don't draw control runes

tests/fonts_megatest.nim

@@ -1,11 +1,12 @@
-import common, pixie, flatty/memoryused
+import common, pixie
 
-# Clone https://github.com/google/fonts
-# Check out commit ebaa6a7aab9b700da4e30a4682687acdf427eae7
+# Clone https://github.com/treeform/fidgetfonts
 
-let fontPaths = findAllFonts("../fonts")
+let fontPaths = findAllFonts("../fidgetfonts")
 
 for fontPath in fontPaths:
   echo fontPath
-  let font = readFont(fontPath)
-  # echo memoryUsed(font)
+  try:
+    var font = readFont(fontPath)
+  except PixieError:
+    echo "ERROR: ", getCurrentExceptionMsg()

tests/test_fonts.nim

@@ -553,3 +553,93 @@ Fifth line""",
   )
 
   doDiff(image, "lines2")
+
+block:
+  var font = readFont("tests/fonts/Roboto-Regular_1.ttf")
+  font.size = 36
+
+  let image = newImage(800, 800)
+  image.fill(rgba(255, 255, 255, 255))
+
+  image.fillText(
+    font,
+    "TopLeft",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haLeft,
+    vAlign = vaTop
+  )
+
+  image.fillText(
+    font,
+    "TopCenter",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haCenter,
+    vAlign = vaTop
+  )
+
+  image.fillText(
+    font,
+    "TopRight",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haRight,
+    vAlign = vaTop
+  )
+
+  image.fillText(
+    font,
+    "MiddleLeft",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haLeft,
+    vAlign = vaMiddle
+  )
+
+  image.fillText(
+    font,
+    "MiddleCenter",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haCenter,
+    vAlign = vaMiddle
+  )
+
+  image.fillText(
+    font,
+    "MiddleRight",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haRight,
+    vAlign = vaMiddle
+  )
+
+  image.fillText(
+    font,
+    "BottomLeft",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haLeft,
+    vAlign = vaBottom
+  )
+
+  image.fillText(
+    font,
+    "BottomCenter",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haCenter,
+    vAlign = vaBottom
+  )
+
+  image.fillText(
+    font,
+    "BottomRight",
+    rgba(0, 0, 0, 255),
+    bounds = image.wh,
+    hAlign = haRight,
+    vAlign = vaBottom
+  )
+
+  doDiff(image, "alignments")