protected override Size MeasureCore(Size availableSize)
{
if (!_dpi.HasValue)
{
_dpi = DpiUtil.GetDpi(this);
}
var drawing = (DoubleUtil.LessThanOrClose(_dpi.Value.X, 96) || HDPIDrawing == null) ? Drawing : HDPIDrawing;
if (drawing != null && !drawing.Bounds.IsEmpty)
{
var bounds = drawing.Bounds;
return(new Size(Math.Min(availableSize.Width, bounds.Width), Math.Min(availableSize.Height, bounds.Height)));
}
return(base.MeasureCore(availableSize));
}
protected override void OnRender(DrawingContext drawingContext)
{
if (!_dpi.HasValue)
{
_dpi = DpiUtil.GetDpi(this);
}
if (Drawing == null || HDPIDrawing == null)
{
drawingContext.DrawDrawing(null);
return;
}
if (DoubleUtil.LessThanOrClose(_dpi.Value.X, 96) || HDPIDrawing == null)
{
RenderOptions.SetEdgeMode(this, EdgeMode.Aliased);
drawingContext.DrawDrawing(Drawing);
}
else
{
RenderOptions.SetEdgeMode(this, EdgeMode.Unspecified);
drawingContext.DrawDrawing(HDPIDrawing);
}
}
private void Redraw()
{
if (_pointsDic.Count == 0)
{
_image.Source = null;
_writeableBitmap = null;
return;
}
//在不初始化 _imageGrid.Width 的前提下，每次生成 WriteableBitmap 都会导致 _imageGrid 的 ActualWidth 自动增大 2 像素左右
//暂未找到原因，故通过赋初值的方式解决
if (DoubleUtil.IsNaN(_imageGrid.Width) || DoubleUtil.IsZero(_imageGrid.Width))
{
_imageGrid.Width = GetCurrentWidth();
}
//当最大化窗体时后，此时，_scrollviewer.ViewportWidth 的值仍然为最大化之前的值，但 _scrollviewer.ActualWidth 已经是变更后的值，且有可能会大于 _scrollviewer.ViewportWidth
//导致只能显示 _scrollviewer.ViewportWidth 大小区域的波形，故通过重置 _imageGrid.Width，间接变更 _scrollviewer.ViewportWidth，与 _scrollviewer.ActualWidth 保持一致
if (_scrollviewer != null && DoubleUtil.GreaterThan(_scrollviewer.ActualWidth, _scrollviewer.ViewportWidth))
{
_imageGrid.Width = _scrollviewer.ActualWidth;
}
if (!_dpi.HasValue)
{
_dpi = DpiUtil.GetDpi(this);
}
var width = (int)GetCurrentWidth();
var height = (int)_imageGrid.ActualHeight;
_writeableBitmap = new WriteableBitmap(width, height, _dpi.Value.X, _dpi.Value.Y, SWM.PixelFormats.Pbgra32, null);
_writeableBitmap.Lock();
using (var backBitmap = new Bitmap(width, height, _writeableBitmap.BackBufferStride, System.Drawing.Imaging.PixelFormat.Format32bppPArgb, _writeableBitmap.BackBuffer))
{
using (var graphics = Graphics.FromImage(backBitmap))
{
graphics.TextRenderingHint = TextRenderingHint.SingleBitPerPixelGridFit;
graphics.SmoothingMode = SmoothingMode.HighQuality;
graphics.Clear(Color.Transparent);
DrawBgLine(graphics, width);
DrawX(graphics, width);
foreach (var kvp in _pointsDic)
{
DrawLine(kvp.Value, graphics, width);
}
graphics.Flush();
}
}
GC.Collect();
_writeableBitmap.AddDirtyRect(new Int32Rect(0, 0, width, height));
_writeableBitmap.Unlock();
_image.Source = _writeableBitmap;
}