我正在尝试将非常大的图像(大约16000x7000像素)加载到Material中,并且我尝试异步加载它。我的第一个尝试是创建一个加载BitmapImage然后将其用于材质的任务:
var bmp = await System.Threading.Tasks.Task.Run(() =>
{
BitmapImage img = new BitmapImage(new Uri(path));
ImageBrush brush = new ImageBrush(img);
var material = new System.Windows.Media.Media3D.DiffuseMaterial(brush);
material.Freeze();
return material;
});
BackMaterial = bmp;
但是我发现的是,在显示材质之前,图像没有加载并扩展到内存中(如果我直接使用ImageBrush,它就会一样)。
我试图避免这种情况,因为它冻结了我的UI,但我没有找到强制位图加载和解码的正确方法。如果我添加一个WriteableBitmap,那么在Task内部执行图片的加载,但是然后我将使用的内存量增加一倍:
var bmp = await System.Threading.Tasks.Task.Run(() =>
{
BitmapImage img = new BitmapImage(new Uri(path));
WriteableBitmap wbmp = new WriteableBitmap(img);
ImageBrush brush = new ImageBrush(wbmp);
var material = new System.Windows.Media.Media3D.DiffuseMaterial(brush);
material.Freeze();
return material;
});
BackMaterial = bmp;
有没有办法强制加载而不会将其加倍到内存中。我也尝试用解码器加载它,但我也加载到内存中两次:
var decoder = BitmapDecoder.Create(new Uri(path), BitmapCreateOptions.PreservePixelFormat,
BitmapCacheOption.None);
var frame = decoder.Frames[0];
int stride = frame.PixelWidth * frame.Format.BitsPerPixel / 8;
byte[] lines = new byte[frame.PixelHeight * stride];
frame.CopyPixels(lines, stride, 0);
var img = BitmapImage.Create(
frame.PixelWidth, frame.PixelHeight, frame.DpiX, frame.DpiY, frame.Format,
frame.Palette, lines, stride);
frame = null;
lines = null;
谢谢!
答案 0 :(得分:5)
我不确定这种异步情况,但你通常会设置BitmapCacheOption.OnLoad强制立即缓存到内存:
var bmp = await System.Threading.Tasks.Task.Run(() =>
{
BitmapImage img = new BitmapImage();
img.BeginInit();
img.CacheOption = BitmapCacheOption.OnLoad;
img.UriSource = new Uri(path);
img.EndInit();
ImageBrush brush = new ImageBrush(img);
...
}