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This commit is contained in:
Ryan Oldenburg 2020-12-03 15:59:46 -06:00
parent a69a4327a0
commit b2cf9776c1
1 changed files with 10 additions and 9 deletions
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19
src/pixie/images.nim
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@ -206,17 +206,17 @@ proc resize*(srcImage: Image, width, height: int): Image =
proc blur*(image: Image, radius: float32): Image = proc blur*(image: Image, radius: float32): Image =
## Applies Gaussian blur to the image given a radius. ## Applies Gaussian blur to the image given a radius.
let radius = (radius).int let radius = radius.int
if radius == 0: if radius == 0:
return image.copy() return image.copy()
# Compute lookup table for 1d Gaussian kernel. # Compute lookup table for 1d Gaussian kernel.
var lookup = newSeq[float](radius*2+1) var lookup = newSeq[float](radius * 2 + 1)
var total = 0.0 var total = 0.0
for xb in -radius .. radius: for xb in -radius .. radius:
let s = radius.float32 / 2.2 # 2.2 matches Figma. let s = radius.float32 / 2.2 # 2.2 matches Figma.
let x = xb.float32 let x = xb.float32
let a = 1/sqrt(2*PI*s^2) * exp(-1*x^2/(2*s^2)) let a = 1 / sqrt(2 * PI * s^2) * exp(-1 * x^2 / (2 * s^2))
lookup[xb + radius] = a lookup[xb + radius] = a
total += a total += a
for xb in -radius .. radius: for xb in -radius .. radius:
@ -266,17 +266,18 @@ proc blur*(image: Image, radius: float32): Image =
proc blurAlpha*(image: Image, radius: float32): Image = proc blurAlpha*(image: Image, radius: float32): Image =
## Applies Gaussian blur to the image given a radius. ## Applies Gaussian blur to the image given a radius.
let radius = (radius).int let radius = radius.int
if radius == 0: if radius == 0:
return image.copy() return image.copy()
# Compute lookup table for 1d Gaussian kernel. # Compute lookup table for 1d Gaussian kernel.
var lookup = newSeq[float](radius*2+1) var
var total = 0.0 lookup = newSeq[float](radius * 2 + 1)
total = 0.0
for xb in -radius .. radius: for xb in -radius .. radius:
let s = radius.float32 / 2.2 # 2.2 matches Figma. let s = radius.float32 / 2.2 # 2.2 matches Figma.
let x = xb.float32 let x = xb.float32
let a = 1/sqrt(2*PI*s^2) * exp(-1*x^2/(2*s^2)) let a = 1 / sqrt(2 * PI * s^2) * exp(-1 * x^2 / (2 * s^2))
lookup[xb + radius] = a lookup[xb + radius] = a
total += a total += a
for xb in -radius .. radius: for xb in -radius .. radius:
@ -291,7 +292,7 @@ proc blurAlpha*(image: Image, radius: float32): Image =
let c2 = image[x + xb, y] let c2 = image[x + xb, y]
let a = lookup[xb + radius] let a = lookup[xb + radius]
alpha += c2.a.float32 * a alpha += c2.a.float32 * a
blurX.setRgbaUnsafe(x, y, rgba(0,0,0, (alpha).uint8)) blurX.setRgbaUnsafe(x, y, rgba(0, 0, 0, alpha.uint8))
# Blur in the Y direction. # Blur in the Y direction.
var blurY = newImage(image.width, image.height) var blurY = newImage(image.width, image.height)
@ -302,7 +303,7 @@ proc blurAlpha*(image: Image, radius: float32): Image =
let c2 = blurX[x, y + yb] let c2 = blurX[x, y + yb]
let a = lookup[yb + radius] let a = lookup[yb + radius]
alpha += c2.a.float32 * a alpha += c2.a.float32 * a
blurY.setRgbaUnsafe(x, y, rgba(0,0,0, (alpha).uint8)) blurY.setRgbaUnsafe(x, y, rgba(0, 0, 0, alpha.uint8))
return blurY return blurY