Add paints to pixie. (#127)

Add paints for: solid, image, image tiled, linear, radial and angular gradients.

examples/paint.nim

@@ -0,0 +1,30 @@
+import pixie
+
+let
+  image = newImage(200, 200)
+
+image.fill(rgba(255, 255, 255, 255))
+image.fillPath(
+  """
+    M 20 60
+    A 40 40 90 0 1 100 60
+    A 40 40 90 0 1 180 60
+    Q 180 120 100 180
+    Q 20 120 20 60
+    z
+  """,
+  Paint(
+    kind:pkGradientRadial,
+    gradientHandlePositions: @[
+      vec2(100, 100),
+      vec2(200, 100),
+      vec2(100, 200)
+    ],
+    gradientStops: @[
+      ColorStop(color:rgba(255, 0, 0, 255).color, position: 0),
+      ColorStop(color:rgba(255, 0, 0, 40).color, position: 1.0),
+    ]
+  )
+)
+
+image.writeFile("examples/paint.png")

src/pixie.nim

@@ -1,9 +1,9 @@
 import bumpy, chroma, flatty/binny, os, pixie/blends, pixie/common,
     pixie/fileformats/bmp, pixie/fileformats/jpg, pixie/fileformats/png,
-    pixie/fileformats/svg, pixie/gradients, pixie/images, pixie/masks,
+    pixie/fileformats/svg, pixie/paints, pixie/images, pixie/masks,
     pixie/paths, vmath
 
-export blends, bumpy, chroma, common, gradients, images, masks, paths, vmath
+export blends, bumpy, chroma, common, paints, images, masks, paths, vmath
 
 type
   FileFormat* = enum

src/pixie/images.nim

@@ -529,6 +529,25 @@ proc getRgbaSmooth*(image: Image, x, y: float32): ColorRGBA =
 
   lerp(bottomMix, topMix, diffY)
 
+proc getRgbaSmoothWrapped*(image: Image, x, y: float32): ColorRGBA =
+  let
+    minX = floor(x)
+    minY = floor(y)
+    diffX = x - minX
+    diffY = y - minY
+    x = minX.int
+    y = minY.int
+
+    x0y0 = image[(x + 0) mod image.width, (y + 0) mod image.height]
+    x1y0 = image[(x + 1) mod image.width, (y + 0) mod image.height]
+    x0y1 = image[(x + 0) mod image.width, (y + 1) mod image.height]
+    x1y1 = image[(x + 1) mod image.width, (y + 1) mod image.height]
+
+    bottomMix = lerp(x0y0, x1y0, diffX)
+    topMix = lerp(x0y1, x1y1, diffX)
+
+  lerp(bottomMix, topMix, diffY)
+
 proc drawCorrect(a, b: Image | Mask, mat = mat3(), blendMode = bmNormal) =
   ## Draws one image onto another using matrix with color blending.
 

src/pixie/paints.nim

@@ -1,9 +1,67 @@
-import chroma, common, images, vmath
+import chroma, common, images, vmath, blends
 
-type ColorStop* = object
-  ## Represents color on a gradient curve.
-  color*: Color
-  position*: float32
+type
+  PaintKind* = enum
+    pkSolid
+    pkImage
+    pkImageTiled
+    pkGradientLinear
+    pkGradientRadial
+    pkGradientAngular
+
+  Paint* = ref object
+    kind*: PaintKind
+    color*: ColorRGBA
+    image*: Image
+    imageMat*: Mat3
+    gradientHandlePositions*: seq[Vec2]
+    gradientStops*: seq[ColorStop]
+    blendMode*: BlendMode
+
+  ColorStop* = object
+    ## Represents color on a gradient curve.
+    color*: Color
+    position*: float32
+
+proc fillImage*(
+  dest: Image,
+  src: Image,
+  mat: Mat3
+) =
+  dest.draw(
+    src,
+    mat
+  )
+
+proc fillImageTiled*(
+  dest: Image,
+  src: Image,
+  mat: Mat3
+) =
+  var
+    matInv = mat.inverse()
+    src = src
+
+  block: # Shrink by 2 as needed
+    const h = 0.5.float32
+    var
+      p = matInv * vec2(0 + h, 0 + h)
+      dx = matInv * vec2(1 + h, 0 + h) - p
+      dy = matInv * vec2(0 + h, 1 + h) - p
+      minFilterBy2 = max(dx.length, dy.length)
+
+    while minFilterBy2 > 2:
+      src = src.minifyBy2()
+      dx /= 2
+      dy /= 2
+      minFilterBy2 /= 2
+      matInv = matInv * scale(vec2(0.5, 0.5))
+
+  for y in 0 ..< dest.height:
+    for x in 0 ..< dest.width:
+      var srcPos = matInv * vec2(x.float32, y.float32)
+      let rgba = src.getRgbaSmoothWrapped(srcPos.x, srcPos.y)
+      dest.setRgbaUnsafe(x,y, rgba)
 
 proc toLineSpace(at, to, point: Vec2): float32 =
   ## Convert position on to where it would fall on a line between at and to.
@@ -88,17 +146,3 @@ proc fillAngularGradient*(
         angle = normalize(xy - center).angle()
         a = (angle + gradientAngle + PI/2).fixAngle() / 2 / PI + 0.5
       image.gradientPut(x, y, a, stops)
-
-proc fillDiamondGradient*(
-  image: Image,
-  center, edge, skew: Vec2,
-  stops: seq[ColorStop]
-) =
-  # TODO: implement GRADIENT_DIAMOND, now will just do GRADIENT_RADIAL
-  let
-    distance = dist(center, edge)
-  for y in 0 ..< image.height:
-    for x in 0 ..< image.width:
-      let xy = vec2(x.float32, y.float32)
-      let a = (center - xy).length() / distance
-      image.gradientPut(x, y, a, stops)

src/pixie/paths.nim

@@ -1,4 +1,4 @@
-import blends, bumpy, chroma, common, images, masks, strutils, vmath
+import blends, bumpy, chroma, common, images, masks, strutils, vmath, paints
 
 when defined(amd64) and not defined(pixieNoSimd):
   import nimsimd/sse2
@@ -1424,6 +1424,53 @@ proc fillPath*(
         segment = transform * segment
   mask.fillShapes(shapes, color, windingRule)
 
+proc fillPath*(
+  image: Image,
+  path: SomePath,
+  paint: Paint,
+  windingRule = wrNonZero,
+) =
+  var mask = newMask(image.width, image.height)
+  var fill = newImage(image.width, image.height)
+  mask.fillPath(parseSomePath(path), windingRule)
+
+  case paint.kind:
+    of pkSolid:
+      fill.fill(paint.color.toPremultipliedAlpha())
+    of pkImage:
+      fill.fillImage(
+        paint.image,
+        paint.imageMat
+      )
+    of pkImageTiled:
+      fill.fillImageTiled(
+        paint.image,
+        paint.imageMat
+      )
+    of pkGradientLinear:
+      fill.fillLinearGradient(
+        paint.gradientHandlePositions[0],
+        paint.gradientHandlePositions[1],
+        paint.gradientStops
+      )
+    of pkGradientRadial:
+      fill.fillRadialGradient(
+        paint.gradientHandlePositions[0],
+        paint.gradientHandlePositions[1],
+        paint.gradientHandlePositions[2],
+        paint.gradientStops
+      )
+    of pkGradientAngular:
+      fill.fillAngularGradient(
+        paint.gradientHandlePositions[0],
+        paint.gradientHandlePositions[1],
+        paint.gradientHandlePositions[2],
+        paint.gradientStops
+      )
+
+  fill.draw(mask, blendMode = bmMask)
+  image.draw(fill, blendMode = paint.blendMode)
+
 proc strokePath*(
   image: Image,
   path: SomePath,

tests/test_paints.nim

@@ -0,0 +1,109 @@
+import chroma, pixie, pixie/fileformats/png, vmath
+
+const heartShape = """
+    M 10,30
+    A 20,20 0,0,1 50,30
+    A 20,20 0,0,1 90,30
+    Q 90,60 50,90
+    Q 10,60 10,30 z
+  """
+
+block:
+  let
+    image = newImage(100, 100)
+  image.fillPath(
+    heartShape,
+    Paint(
+      kind:pkSolid,
+      color:rgba(255, 0, 0, 255)
+    )
+  )
+  image.writeFile("tests/images/paths/paintSolid.png")
+
+block:
+  let
+    image = newImage(100, 100)
+  image.fillPath(
+    heartShape,
+    Paint(
+      kind:pkImage,
+      image:decodePng(readFile("tests/images/png/baboon.png")),
+      imageMat:scale(vec2(0.2, 0.2))
+    )
+  )
+  image.writeFile("tests/images/paths/paintImage.png")
+
+block:
+  let
+    image = newImage(100, 100)
+  image.fillPath(
+    heartShape,
+    Paint(
+      kind:pkImageTiled,
+      image:decodePng(readFile("tests/images/png/baboon.png")),
+      imageMat:scale(vec2(0.02, 0.02))
+    )
+  )
+  image.writeFile("tests/images/paths/paintImageTiled.png")
+
+
+block:
+  let
+    image = newImage(100, 100)
+  image.fillPath(
+    heartShape,
+    Paint(
+      kind:pkGradientLinear,
+      gradientHandlePositions: @[
+        vec2(0, 50),
+        vec2(100, 50),
+      ],
+      gradientStops: @[
+        ColorStop(color:rgba(255, 0, 0, 255).color, position: 0),
+        ColorStop(color:rgba(255, 0, 0, 40).color, position: 1.0),
+      ]
+    )
+  )
+  image.writeFile("tests/images/paths/gradientLinear.png")
+
+block:
+  let
+    image = newImage(100, 100)
+  image.fillPath(
+    heartShape,
+    Paint(
+      kind:pkGradientRadial,
+      gradientHandlePositions: @[
+        vec2(50, 50),
+        vec2(100, 50),
+        vec2(50, 100)
+      ],
+      gradientStops: @[
+        ColorStop(color:rgba(255, 0, 0, 255).color, position: 0),
+        ColorStop(color:rgba(255, 0, 0, 40).color, position: 1.0),
+      ]
+    )
+  )
+
+  image.writeFile("tests/images/paths/gradientRadial.png")
+
+block:
+  let
+    image = newImage(100, 100)
+  image.fillPath(
+    heartShape,
+    Paint(
+      kind:pkGradientAngular,
+      gradientHandlePositions: @[
+        vec2(50, 50),
+        vec2(100, 50),
+        vec2(50, 100)
+      ],
+      gradientStops: @[
+        ColorStop(color:rgba(255, 0, 0, 255).color, position: 0),
+        ColorStop(color:rgba(255, 0, 0, 40).color, position: 1.0),
+      ]
+    )
+  )
+
+  image.writeFile("tests/images/paths/gradientAngular.png")