1
我有一個問題system.drawing和WPF之間的互操作問題。爲了簡化這個問題,我構建了一個例子來說明問題。我使用System.Drawing繪製,然後使用CreateBitmapSourceFromHBitmap將結果複製到System.Windows.Controls.Image。不知何故,你可以在屏幕截圖中看到alpha信息丟失。System.Drawing和WPF互操作 - CreateBitmapSourceFromHBitmap
在透明位圖上繪製黑色文本,然後將其複製到透明的圖像組件。父網格本身具有黑色背景。我猜想,結果是一個完全黑色的圖像,但它不是,文本似乎在進行抗鋸齒時使用白色作爲背景進行繪製。
下面是MainWindow.xaml代碼:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid Name="grid" Background="Black">
<Image Name="image" Stretch="Fill" Loaded="image_Loaded"></Image>
</Grid>
</Window>
而對於MainWindow.xaml.cs代碼:
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
using System.Windows;
namespace WpfApplication1
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void image_Loaded(object sender, RoutedEventArgs e)
{
//use system drawing to draw text
Bitmap bmp = new Bitmap ((Int32) grid.ActualWidth, (Int32) grid.ActualHeight);
Graphics graphics = Graphics.FromImage (bmp);
var brush = new SolidBrush(Color.FromArgb(255, 0, 0, 0));
var font = new Font(System.Drawing.FontFamily.GenericSansSerif, 30.0f, System.Drawing.FontStyle.Regular, GraphicsUnit.Pixel);
graphics.Clear(Color.Transparent);
graphics.SmoothingMode = SmoothingMode.HighQuality;
graphics.CompositingMode = CompositingMode.SourceOver;
graphics.CompositingQuality = CompositingQuality.HighQuality;
//draw text
graphics.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
graphics.TextContrast = 5;
graphics.DrawString("My Text", font, brush, 10, 10);
//try saving
bmp.Save("E:\\temp.png", System.Drawing.Imaging.ImageFormat.Png);
//back to wpf image control
image.Source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap (bmp.GetHbitmap (), IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromWidthAndHeight ((Int32) grid.ActualWidth, (Int32) grid.ActualHeight));
}
}
}
有誰經歷過這一點?我怎樣纔能有一個平滑的抗鋸齒效果,它不會與白色相乘?
你不需要這個骯髒的黑客來釋放文件...保存完成後關閉文件。無論如何,你總是可以調用bmp.Dispose明確地 – 2011-05-02 10:13:24
是的,我想是的 - 當時沒有想到。我會修復我的答案,並將其排除以避免混淆。 – epxp 2011-05-02 17:02:07