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comparison semiconginev2/image.nim @ 1242:e8b3dc80e48e

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add: PNG loading and tests for it
author sam <sam@basx.dev>
date Mon, 22 Jul 2024 15:53:32 +0700
parents
children c15770761865
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1241:a0ed1a918fda 1242:e8b3dc80e48e
1 type
2 Gray* = TVec1[uint8]
3 RGBA* = TVec4[uint8]
4 PixelType* = Gray | RGBA
5 Image*[T: PixelType] = object
6 width*: uint32
7 height*: uint32
8 interpolation*: VkFilter = VK_FILTER_LINEAR
9 data*: seq[T]
10 vk*: VkImage
11 imageview*: VkImageView
12 sampler*: VkSampler
13 isRenderTarget*: bool = false
14 samples*: VkSampleCountFlagBits = VK_SAMPLE_COUNT_1_BIT
15
16 proc LoadImage*[T: PixelType](path: string, package = DEFAULT_PACKAGE): Image[T] =
17 assert path.splitFile().ext.toLowerAscii == ".png"
18 when T is Gray:
19 let pngType = 0.cint
20 elif T is RGBA:
21 let pngType = 6.cint
22
23 let indata = loadResource_intern(path, package = package).readAll()
24 var w, h: cuint
25 var data: cstring
26
27 if lodepng_decode_memory(out_data = addr(data), w = addr(w), h = addr(h), in_data = cstring(indata), insize = csize_t(indata.len), colorType = pngType, bitdepth = 8) != 0:
28 raise newException(Exception, "An error occured while loading PNG file")
29
30 let imagesize = w * h * 4
31 result = Image[T](width: w, height: h, data: newSeq[T](w * h))
32 copyMem(result.data.ToCPointer, data, imagesize)
33 nativeFree(data)
34
35 when T is RGBA: # converkt to BGRA
36 for i in 0 ..< result.data.len:
37 swap(result.data[i][0], result.data[i][2])
38
39 proc toPNG[T: PixelType](image: Image[T]): seq[uint8] =
40 when T is Gray:
41 let pngType = 0 # hardcoded in lodepng.h
42 else:
43 let pngType = 6 # hardcoded in lodepng.h
44 var
45 pngData: cstring
46 pngSize: csize_t
47 for y in 0 ..< image.height:
48 for x in 0 ..< image.width:
49 discard
50 let ret = lodepng_encode_memory(
51 addr pngData,
52 addr pngSize,
53 cast[cstring](image.imagedata.ToCPointer),
54 cuint(image.width),
55 cuint(image.height),
56 cint(pngType),
57 8,
58 )
59 assert ret == 0, &"There was an error with generating the PNG data for image {image}, result was: {ret}"
60 result = newSeq[uint8](pngSize)
61 for i in 0 ..< pngSize:
62 result[i] = uint8(pngData[i])
63 nativeFree(pngData)
64
65 proc WritePNG*(image: Image, filename: string) =
66 let f = filename.open(mode = fmWrite)
67 let data = image.toPNG()
68 let written = f.writeBytes(data, 0, data.len)
69 assert written == data.len, &"There was an error while saving '{filename}': only {written} of {data.len} bytes were written"
70 f.close()