//创建直方图
private void DrawHistogram(CanvasDrawingSession drawingSession, Size size, EffectChannelSelect channelSelect, CanvasLinearGradientBrush brush)
{
int binCount = (int)CanvasControl.ActualWidth; //256;//矩形数量
const float graphPower = 0.25f; // 非线性规模使得图更清楚地显示微小的变化。
try
{
float[] histogram = CanvasImage.ComputeHistogram(App.Model.MainRenderTarget, App.Model.MainRenderTarget.Bounds, drawingSession, channelSelect, binCount);
var w = (float)size.Width / binCount;
var h = (float)size.Height;
for (int i = 0; i < binCount; i++)
{
var x = i * w;
var y = (1 - (float)Math.Pow(histogram[i], graphPower)) * h;
brush.StartPoint = new Vector2(x, y);
brush.EndPoint = new Vector2(x, h);
drawingSession.FillRectangle(x, y, w, h - y, brush);
}
}
catch (Exception) { }
}
void DrawHistogram(CanvasDrawingSession drawingSession, Size size, EffectChannelSelect channelSelect, CanvasLinearGradientBrush brush)
{
const int binCount = 64;
const float graphPower = 0.25f; // Nonlinear scale makes the graph show small changes more clearly.
float[] histogram = CanvasImage.ComputeHistogram(hueEffect, bitmap.Bounds, drawingSession, channelSelect, binCount);
var w = (float)size.Width / binCount;
var h = (float)size.Height;
for (int i = 0; i < binCount; i++)
{
var x = i * w;
var y = (1 - (float)Math.Pow(histogram[i], graphPower)) * h;
brush.StartPoint = new Vector2(x, y);
brush.EndPoint = new Vector2(x, h);
drawingSession.FillRectangle(x, y, w, h - y, brush);
}
}
static void TestHistogram(CanvasBitmap bitmap, Rect sourceRectangle, EffectChannelSelect channelSelect, params float[] expected)
{
var histogram = CanvasImage.ComputeHistogram(bitmap, sourceRectangle, bitmap.Device, channelSelect, 2);
CollectionAssert.AreEqual(expected, histogram);
}
