From 5afa5720dbdd7050e5e013664e9bf0caa8239ba4 Mon Sep 17 00:00:00 2001
From: Ryan Oldenburg <ryan@guzba.com>
Date: Wed, 15 Jun 2022 14:03:28 -0500
Subject: [PATCH] faster on arc, arc string []= issue 18339
---
src/pixie/fileformats/png.nim | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/src/pixie/fileformats/png.nim b/src/pixie/fileformats/png.nim
index ae6acda..d6986de 100644
--- a/src/pixie/fileformats/png.nim
+++ b/src/pixie/fileformats/png.nim
@@ -94,7 +94,7 @@ proc decodePalette(data: pointer, len: int): seq[ColorRGB] =
proc unfilter(
uncompressed: string, height, rowBytes, bpp: int
-): string =
+): seq[uint8] =
result.setLen(uncompressed.len - height)
template uncompressedIdx(x, y: int): int =
@@ -121,7 +121,7 @@ proc unfilter(
var value = uncompressed.readUint8(uncompressedStartIdx + x)
if x - bpp >= 0:
value += result.readUint8(unfilteredStartIx + x - bpp)
- result[unfilteredStartIx + x] = value.char
+ result[unfilteredStartIx + x] = value
of 2: # Up
let
uncompressedStartIdx = uncompressedIdx(1, y)
@@ -129,8 +129,8 @@ proc unfilter(
for x in 0 ..< rowBytes:
var value = uncompressed.readUint8(uncompressedStartIdx + x)
if y - 1 >= 0:
- value += result.readUint8(unfiteredIdx(x, y - 1))
- result[unfilteredStartIx + x] = value.char
+ value += result.readUint8(unfilteredStartIx + x - rowBytes)
+ result[unfilteredStartIx + x] = value
of 3: # Average
let
uncompressedStartIdx = uncompressedIdx(1, y)
@@ -144,7 +144,7 @@ proc unfilter(
if y - 1 >= 0:
up = result[unfilteredStartIx + x - rowBytes].int
value += ((left + up) div 2).uint8
- result[unfilteredStartIx + x] = value.char
+ result[unfilteredStartIx + x] = value
of 4: # Paeth
let
uncompressedStartIdx = uncompressedIdx(1, y)
@@ -172,7 +172,7 @@ proc unfilter(
else:
c
value += paethPredictor(up, left, upLeft).uint8
- result[unfilteredStartIx + x] = value.char
+ result[unfilteredStartIx + x] = value
else:
discard # Not possible, parseHeader validates