mirror of https://github.com/status-im/nimPNG.git
89 lines
2.2 KiB
Nim
89 lines
2.2 KiB
Nim
import streams, os, strutils, nimPNG
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type
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BMP = ref object
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width, height: int
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data: string
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proc writeWORD(s: Stream, val: int) =
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let word = val.int16
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s.write(word)
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proc writeDWORD(s: Stream, val: int) =
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let dword = val.int32
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s.write(dword)
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proc newBMP(w, h: int): BMP =
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new(result)
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result.width = w
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result.height = h
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result.data = newString(w * h * 3)
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proc write(s: Stream, bmp: BMP) =
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let stride = 4 * ((bmp.width * 24 + 31) div 32)
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let imageData = stride * bmp.height
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let offset = 54
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var fileSize = imageData + offset
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s.writeWORD(19778)
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s.writeDWORD(fileSize)
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s.writeWORD(0)
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s.writeWORD(0)
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s.writeDWORD(offset)
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s.writeDWORD(40)
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s.writeDWORD(bmp.width)
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s.writeDWORD(bmp.height)
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s.writeWORD(1)
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s.writeWORD(24)
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s.writeDWORD(0)
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s.writeDWORD(imageData)
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s.writeDWORD(3780)
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s.writeDWORD(3780)
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s.writeDWORD(0)
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s.writeDWORD(0)
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let bytesPerRow = bmp.width * 3
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let paddingLen = stride - bytesPerRow
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let padding = if paddingLen > 0: newString(paddingLen) else: nil
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for i in 0..bmp.height-1:
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s.writeData(addr(bmp.data[i * bytesPerRow]), bytesPerRow)
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if paddingLen > 0: s.write(padding)
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proc loadPNG(fileName: string): BMP =
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var settings = makePNGDecoder()
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settings.readTextChunks = true
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var png = loadPNG24(fileName, settings)
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if png == nil: return nil
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let size = png.width * png.height
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result = newBMP(png.width, png.height)
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for i in 0..size-1:
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let px = i * 3
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result.data[px] = png.data[px]
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result.data[px + 1] = png.data[px + 1]
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result.data[px + 2] = png.data[px + 2]
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proc write(bmp: BMP): string =
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var s = newStringStream()
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s.write(bmp)
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result = s.data
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proc convert(dir: string) =
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for fileName in walkDirRec(dir, {pcFile}):
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let path = splitFile(fileName)
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if path.ext.len() == 0: continue
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let ext = toLower(path.ext)
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if ext != ".png": continue
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if path.name[0] == 'x': continue
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let bmpName = path.dir & DirSep & path.name & ExtSep & "bmp"
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echo fileName, " vs. ", bmpName
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var bmp = loadPNG(fileName)
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if bmp != nil:
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let data1 = bmp.write()
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let data2 = readFile(bmpName)
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assert data1 == data2
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convert("suite")
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