我有像素艺术创作者程序,我在画布上有一个矩形(像素?)。这是很好的解决方案,不是很大的(例如128x128)。如果我想在画布上创建1024x1024矩形,这个过程非常长,ram的使用量大约是1-2 gb,之后程序运行得非常慢。如何优化这一点,或创造更好的解决方案?
使用Rectangle
来表示每个像素是错误的方法。作为FrameworkElement
,每个矩形都参与布局和输入命中测试。这种方法太重,无法扩展。现在放弃它。
我建议直接绘制到WriteableBitmap
并使用自定义曲面在用户绘制时渲染位图。
以下是允许简单绘制单一颜色的概念证明。它需要可从NuGet获得的WriteableBitmapEx库。
public class PixelEditor : FrameworkElement
{
private readonly Surface _surface;
private readonly Visual _gridLines;
public int PixelWidth { get; } = 128;
public int PixelHeight { get; } = 128;
public int Magnification { get; } = 10;
public PixelEditor()
{
_surface = new Surface(this);
_gridLines = CreateGridLines();
Cursor = Cursors.Pen;
AddVisualChild(_surface);
AddVisualChild(_gridLines);
}
protected override int VisualChildrenCount => 2;
protected override Visual GetVisualChild(int index)
{
return index == 0 ? _surface : _gridLines;
}
private void Draw()
{
var p = Mouse.GetPosition(_surface);
var magnification = Magnification;
var surfaceWidth = PixelWidth * magnification;
var surfaceHeight = PixelHeight * magnification;
if (p.X < 0 || p.X >= surfaceWidth || p.Y < 0 || p.Y >= surfaceHeight)
return;
_surface.SetColor(
(int)(p.X / magnification),
(int)(p.Y / magnification),
Colors.DodgerBlue);
_surface.InvalidateVisual();
}
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (e.LeftButton == MouseButtonState.Pressed && IsMouseCaptured)
Draw();
}
protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
{
base.OnMouseLeftButtonDown(e);
CaptureMouse();
Draw();
}
protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)
{
base.OnMouseLeftButtonUp(e);
ReleaseMouseCapture();
}
protected override Size MeasureOverride(Size availableSize)
{
var magnification = Magnification;
var size = new Size(PixelWidth* magnification, PixelHeight * magnification);
_surface.Measure(size);
return size;
}
protected override Size ArrangeOverride(Size finalSize)
{
_surface.Arrange(new Rect(finalSize));
return finalSize;
}
private Visual CreateGridLines()
{
var dv = new DrawingVisual();
var dc = dv.RenderOpen();
var w = PixelWidth;
var h = PixelHeight;
var m = Magnification;
var d = -0.5d; // snap gridlines to device pixels
var pen = new Pen(new SolidColorBrush(Color.FromArgb(63, 63, 63, 63)), 1d);
pen.Freeze();
for (var x = 1; x < w; x++)
dc.DrawLine(pen, new Point(x * m + d, 0), new Point(x * m + d, h * m));
for (var y = 1; y < h; y++)
dc.DrawLine(pen, new Point(0, y * m + d), new Point(w * m, y * m + d));
dc.Close();
return dv;
}
private sealed class Surface : FrameworkElement
{
private readonly PixelEditor _owner;
private readonly WriteableBitmap _bitmap;
public Surface(PixelEditor owner)
{
_owner = owner;
_bitmap = BitmapFactory.New(owner.PixelWidth, owner.PixelHeight);
_bitmap.Clear(Colors.White);
RenderOptions.SetBitmapScalingMode(this, BitmapScalingMode.NearestNeighbor);
}
protected override void OnRender(DrawingContext dc)
{
base.OnRender(dc);
var magnification = _owner.Magnification;
var width = _bitmap.PixelWidth * magnification;
var height = _bitmap.PixelHeight * magnification;
dc.DrawImage(_bitmap, new Rect(0, 0, width, height));
}
internal void SetColor(int x, int y, Color color)
{
_bitmap.SetPixel(x, y, color);
}
}
}
只需将其导入您的Xaml,最好在ScrollViewer
内:
<Window x:Class="WpfTest.PixelArtEditor"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:l="clr-namespace:WpfTest"
Title="PixelArtEditor"
Width="640"
Height="480">
<ScrollViewer HorizontalScrollBarVisibility="Auto"
VerticalScrollBarVisibility="Auto">
<l:PixelEditor />
</ScrollViewer>
</Window>
显然,这与功能齐全的像素艺术编辑器相差甚远,但它功能齐全,足以让你走上正轨。编辑128x128图像与1024x1024之间的内存使用量差异约为30mb。启动并查看它的运行情况:
嘿,这很有趣!谢谢你的转移。
只是为了改进Mike Strobel解决方案,将网格线捕捉到设备像素。
var d = -0.5d; // snap gridlines to device pixels
using (DrawingContext dc = _dv.RenderOpen())
{
GuidelineSet guidelineSet = new GuidelineSet();
guidelineSet.GuidelinesX.Add(0.5);
guidelineSet.GuidelinesY.Add(0.5);
dc.PushGuidelineSet(guidelineSet);
// Draw grid
}