Merge pull request #298 from guzba/master

blur 2x faster for images

src/pixie/images.nim

@@ -475,10 +475,10 @@ proc blur*(
 
   template rgbx(values: array[4, uint32]): ColorRGBX =
     rgbx(
-      (values[0] div 1024 div 255).uint8,
-      (values[1] div 1024 div 255).uint8,
-      (values[2] div 1024 div 255).uint8,
-      (values[3] div 1024 div 255).uint8
+      (values[0] div 256 div 255).uint8,
+      (values[1] div 256 div 255).uint8,
+      (values[2] div 256 div 255).uint8,
+      (values[3] div 256 div 255).uint8
     )
 
   # Blur in the X direction. Store with dimensions swapped for reading later.
@@ -488,13 +488,10 @@ proc blur*(
       var values: array[4, uint32]
       for xx in x - radius ..< min(x + radius, 0):
         values += outOfBounds * kernel[xx - x + radius]
-
       for xx in max(x - radius, 0) .. min(x + radius, image.width - 1):
         values += image.getRgbaUnsafe(xx, y) * kernel[xx - x + radius]
-
       for xx in max(x - radius, image.width) .. x + radius:
         values += outOfBounds * kernel[xx - x + radius]
-
       blurX.setRgbaUnsafe(y, x, rgbx(values))
 
   # Blur in the Y direction.
@@ -503,13 +500,10 @@ proc blur*(
       var values: array[4, uint32]
       for yy in y - radius ..< min(y + radius, 0):
         values += outOfBounds * kernel[yy - y + radius]
-
       for yy in max(y - radius, 0) .. min(y + radius, image.height - 1):
         values += blurX.getRgbaUnsafe(yy, x) * kernel[yy - y + radius]
-
       for yy in max(y - radius, image.height) .. y + radius:
         values += outOfBounds * kernel[yy - y + radius]
-
       image.setRgbaUnsafe(x, y, rgbx(values))
 
 proc newMask*(image: Image): Mask {.raises: [PixieError].} =

src/pixie/internal.nim

@@ -3,9 +3,9 @@ import chroma, vmath
 when defined(amd64) and not defined(pixieNoSimd):
   import nimsimd/sse2
 
-proc gaussianKernel*(radius: int): seq[uint32] {.raises: [].} =
+proc gaussianKernel*(radius: int): seq[uint16] {.raises: [].} =
   ## Compute lookup table for 1d Gaussian kernel.
-  ## Values are [0, 255] * 1024.
+  ## Values are [0, 255] * 256.
   result.setLen(radius * 2 + 1)
 
   var
@@ -19,9 +19,8 @@ proc gaussianKernel*(radius: int): seq[uint32] {.raises: [].} =
     total += a
   for step in -radius .. radius:
     floats[step + radius] = floats[step + radius] / total
-
   for i, f in floats:
-    result[i] = round(f * 255 * 1024).uint32
+    result[i] = round(f * 255 * 256).uint16
 
 proc applyOpacity*(color: ColorRGBX, opacity: float32): ColorRGBX {.raises: [].} =
   if opacity == 0:

src/pixie/masks.nim

@@ -275,30 +275,24 @@ proc blur*(mask: Mask, radius: float32, outOfBounds: uint8 = 0) {.raises: [Pixie
     for x in 0 ..< mask.width:
       var value: uint32
       for xx in x - radius ..< min(x + radius, 0):
-        value += outOfBounds * kernel[xx - x + radius]
-
+        value += outOfBounds * kernel[xx - x + radius].uint32
       for xx in max(x - radius, 0) .. min(x + radius, mask.width - 1):
-        value += mask.getValueUnsafe(xx, y) * kernel[xx - x + radius]
-
+        value += mask.getValueUnsafe(xx, y) * kernel[xx - x + radius].uint32
       for xx in max(x - radius, mask.width) .. x + radius:
-        value += outOfBounds * kernel[xx - x + radius]
-
-      blurX.setValueUnsafe(y, x, (value div 1024 div 255).uint8)
+        value += outOfBounds * kernel[xx - x + radius].uint32
+      blurX.setValueUnsafe(y, x, (value div 256 div 255).uint8)
 
   # Blur in the Y direction and modify image.
   for y in 0 ..< mask.height:
     for x in 0 ..< mask.width:
       var value: uint32
       for yy in y - radius ..< min(y + radius, 0):
-        value += outOfBounds * kernel[yy - y + radius]
-
+        value += outOfBounds * kernel[yy - y + radius].uint32
       for yy in max(y - radius, 0) .. min(y + radius, mask.height - 1):
-        value += blurX.getValueUnsafe(yy, x) * kernel[yy - y + radius]
-
+        value += blurX.getValueUnsafe(yy, x) * kernel[yy - y + radius].uint32
       for yy in max(y - radius, mask.height) .. y + radius:
-        value += outOfBounds * kernel[yy - y + radius]
-
-      mask.setValueUnsafe(x, y, (value div 1024 div 255).uint8)
+        value += outOfBounds * kernel[yy - y + radius].uint32
+      mask.setValueUnsafe(x, y, (value div 256 div 255).uint8)
 
 when defined(release):
   {.pop.}

tests/benchmark_images_blur.nim

@@ -41,13 +41,10 @@ proc blurSlower*(
       var values: array[4, uint32]
       for xx in x - radius ..< min(x + radius, 0):
         values += outOfBounds * kernel[xx - x + radius]
-
       for xx in max(x - radius, 0) .. min(x + radius, image.width - 1):
         values += image.getRgbaUnsafe(xx, y) * kernel[xx - x + radius]
-
       for xx in max(x - radius, image.width) .. x + radius:
         values += outOfBounds * kernel[xx - x + radius]
-
       blurX.setRgbaUnsafe(x, y, rgbx(values))
 
   # Blur in the Y direction.
@@ -56,13 +53,10 @@ proc blurSlower*(
       var values: array[4, uint32]
       for yy in y - radius ..< min(y + radius, 0):
         values += outOfBounds * kernel[yy - y + radius]
-
       for yy in max(y - radius, 0) .. min(y + radius, image.height - 1):
         values += blurX.getRgbaUnsafe(x, yy) * kernel[yy - y + radius]
-
       for yy in max(y - radius, image.height) .. y + radius:
         values += outOfBounds * kernel[yy - y + radius]
-
       image.setRgbaUnsafe(x, y, rgbx(values))
 
 let image = newImage(1920, 1080)