如何在Haskell中将SVG光栅化为SDL.Surface?
我正在使用和。我想绘制SVG图像,但sdl2图像不支持此格式(请参阅): SDL_图像是一个图像文件加载库。如何在Haskell中将SVG光栅化为SDL.Surface?,haskell,svg,sdl-2,haskell-stack,haskell-sdl,Haskell,Svg,Sdl 2,Haskell Stack,Haskell Sdl,我正在使用和。我想绘制SVG图像,但sdl2图像不支持此格式(请参阅): SDL_图像是一个图像文件加载库。 它将图像加载为SDL曲面和纹理,并支持以下格式:BMP、GIF、JPEG、LBM、PCX、PNG、PNM、TGA、TIFF、WEBP、XCF、XPM、XV 如何加载SVG、缩放/调整SVG大小并将其栅格化为SDL.Surface或SDL.Texture 编辑: 在C++中你可以使用库: 我还没有用真正的代码对此进行测试,但希望它在正确的轨道上: 获取一个IO(图像像素RGBA8),其中结
它将图像加载为SDL曲面和纹理,并支持以下格式:BMP、GIF、JPEG、LBM、PCX、PNG、PNM、TGA、TIFF、WEBP、XCF、XPM、XV 如何加载SVG、缩放/调整SVG大小并将其栅格化为
SDL.Surface
或SDL.Texture
编辑:
在C++中你可以使用库:
我还没有用真正的代码对此进行测试,但希望它在正确的轨道上: 获取一个
IO(图像像素RGBA8)
,其中结果类型来自JuicyPixels图像库
获取一个(Storable
)向量(PixelBaseComponent PixelRGBA8)
,在跟踪所有类型后,我猜它是一个向量字8
或者(阅读文档了解重要的安全信息)为您获取不可变的
向量的可变副本(或视图,用于不安全的变体)
您尝试了什么?“sdl2图像不支持此格式”是什么意思?如果你相信这些LIBS可能是可行的,我猜你可以编写相应的C程序——如果是的话,请随意加入这个程序。我添加了一个C++解决方案,使用NANOSVG并引用SDL2图像的支持图像格式。这是离题的。只需谷歌“Haskell SVG渲染器”,您应该可以找到一些选项。我的例子是C++,需要另一个库NANOSVG。您必须对图像数据执行静态\u cast
。Haskell的SDL.createRGBSurfaceFrom
期望Data.Vector.Storable.Mutable.VectorIO Word8
作为图像数据。我不知道如何在有库或没有库的情况下获取这种类型的图像数据。根据您的建议,我在问题中添加了一个运行示例。但是,它没有呈现正确的结果。我想我必须要转换像素数据。@ MaiMIC我想你可能需要把音高设置为宽度的4倍,就像你的C++例子一样。我忽略了这一点。我还忽略了使用abgr888
而不是rgba888
@maiermit SDL/OpenGL和Rasterific.Svg(rgba888 vs abgr888)中的像素格式不匹配的原因是什么?我不确定,我理解你的问题。您对我的跑步示例的固定版本感兴趣吗?
NSVGimage * svg_image = nsvgParseFromFile(filepath.c_str(), "px", 96.0);
std::vector<Uint8> img_data;
img_data.resize(width * height * 4);
NSVGrasterizer * rasterizer = nsvgCreateRasterizer()
nsvgRasterize(rasterizer,
svg_image, 0,0,1,
img_data.data(),
width, height,
width * 4);
SDL_Surface * surface = SDL_CreateRGBSurfaceFrom(
static_cast<void *>(img_data.data()),
width, height,
32, // depth
4 * width, // pitch
0x000000FF, // red mask
0x0000FF00, // green mask
0x00FF0000, // blue mask
0xFF000000 // alpha mask (alpha in this format)
);
{-# LANGUAGE OverloadedStrings #-}
module Main where
import Codec.Picture
import Codec.Picture.Types
import Data.Vector.Storable.Mutable (IOVector)
import Data.Vector.Generic (thaw)
import Graphics.Rasterific.Svg
(loadCreateFontCache, renderSvgDocument)
import Graphics.Svg (loadSvgFile)
import Data.Function (fix)
import Data.Word (Word8)
import Control.Monad as CM
import qualified Data.Vector.Generic.Mutable as GM
import Data.Vector.Storable (Vector)
import qualified Data.Vector.Storable as V
import Foreign.C.Types (CInt)
import qualified SDL
import SDL.Vect (Point(P), V2(V2), V4(V4))
import Control.Concurrent (threadDelay)
import SDL (($=))
import Paths_render_svg_in_sdl2_haskell (getDataFileName)
screenWidth, screenHeight :: CInt
(screenWidth, screenHeight) = (1280, 720)
-- SDL dependency: sudo apt-get install libsdl2-dev
main :: IO ()
main = do
SDL.initialize [SDL.InitVideo, SDL.InitTimer, SDL.InitEvents]
-- ensure render quality
SDL.HintRenderScaleQuality $= SDL.ScaleLinear
do renderQuality <- SDL.get SDL.HintRenderScaleQuality
CM.when (renderQuality /= SDL.ScaleLinear) $
putStrLn "Warning: Linear texture filtering not enabled!"
window <-
SDL.createWindow
"Load and render SVG"
SDL.defaultWindow
{ SDL.windowPosition = SDL.Centered
, SDL.windowInitialSize = V2 screenWidth screenHeight
}
SDL.showWindow window
renderer <-
SDL.createRenderer
window
(-1)
SDL.RendererConfig
{ SDL.rendererType = SDL.AcceleratedVSyncRenderer
, SDL.rendererTargetTexture = True
}
SDL.rendererDrawColor renderer $= V4 maxBound maxBound maxBound maxBound
SDL.clear renderer
renderSvgExample renderer
SDL.present renderer
threadDelay 2000000
SDL.destroyRenderer renderer
SDL.destroyWindow window
SDL.quit
renderSvgExample :: SDL.Renderer -> IO ()
renderSvgExample renderer = do
mimage <- getDataFileName "thumbs-up.svg" >>= loadSVGImage
case mimage of
Nothing -> putStrLn "Image convertion failed."
(Just image) -> do
let surfaceSize :: V2 CInt
surfaceSize = V2 screenWidth screenHeight
surface <- createSurfaceFromSVG image surfaceSize
texture <- SDL.createTextureFromSurface renderer surface
SDL.freeSurface surface
let source = SDL.Rectangle (P $ V2 0 0) surfaceSize
dest = SDL.Rectangle (P $ V2 0 0) surfaceSize
angle = 0.0
center = Nothing
flipNone = V2 False False
SDL.copyEx
renderer
texture
(Just source)
(Just dest)
angle
center
flipNone
SDL.destroyTexture texture
createSurfaceFromSVG :: Image PixelRGBA8 -> V2 CInt -> IO SDL.Surface
createSurfaceFromSVG image surfaceSize = do
let rawImageData :: Vector Word8
rawImageData = imageData image
imWidth :: Int
imWidth = imageWidth image
pitch :: CInt
pitch = fromIntegral imWidth
mutableVector <- convertToMutableVector rawImageData
SDL.createRGBSurfaceFrom mutableVector surfaceSize pitch SDL.RGBA8888
convertToMutableVector :: Vector Word8 -> IO (IOVector Word8)
convertToMutableVector= thaw
loadSVGImage :: FilePath -> IO (Maybe (Image PixelRGBA8))
loadSVGImage filepath = do
mdoc <- loadSvgFile filepath
case mdoc of
Nothing -> return Nothing
Just doc -> do
cache <- loadCreateFontCache "fonty-texture-cache"
(finalImage, _) <- renderSvgDocument cache Nothing 96 doc
return $ Just finalImage