我注意到,在OnPaint事件中进行图形变换缩放后,图像的第一个像素列的一半没有绘制出来。
要复现这个问题所需的所有代码都在帖子的末尾。基本上,我创建了一个从PictureBox派生的类,名为PictureBox2,并重写了OnPaint方法以执行缩放变换。它还将InterpolationMode更改为NearestNeighbor,以防止Graphics改变像素的外观。
PictureBox控件被添加到一个名为Form6_GraphicsTest的窗体中。该控件在所有边上都有锚定。PictureBox2的背景颜色被更改为蓝色,窗体的背景颜色被更改为深灰色。
正如您在下面的图像中所看到的,只有图像的第一个像素列的1/2被绘制出来。为什么会这样呢?我有什么遗漏吗?
以下是原始的10x10 8bpp图像:
编辑-解决方案 由于某种奇怪的原因,PixelOffsetMode.Default会消耗0.5个像素。解决方案:使用PixelOffsetMode.Half或HighQuality!
要复现这个问题所需的所有代码都在帖子的末尾。基本上,我创建了一个从PictureBox派生的类,名为PictureBox2,并重写了OnPaint方法以执行缩放变换。它还将InterpolationMode更改为NearestNeighbor,以防止Graphics改变像素的外观。
PictureBox控件被添加到一个名为Form6_GraphicsTest的窗体中。该控件在所有边上都有锚定。PictureBox2的背景颜色被更改为蓝色,窗体的背景颜色被更改为深灰色。
正如您在下面的图像中所看到的,只有图像的第一个像素列的1/2被绘制出来。为什么会这样呢?我有什么遗漏吗?
以下是原始的10x10 8bpp图像:
编辑-解决方案 由于某种奇怪的原因,PixelOffsetMode.Default会消耗0.5个像素。解决方案:使用PixelOffsetMode.Half或HighQuality!
代码 PictureBox2.cs
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
namespace GraphicsTest
{
public class PictureBox2 : PictureBox
{
public PointF Zoom = new PointF(20, 20);
private InterpolationMode interpolationMode = InterpolationMode.NearestNeighbor;
/// <summary>
/// Paint the image
/// </summary>
/// <param name="e">The paint event</param>
protected override void OnPaint(PaintEventArgs e)
{
if (IsDisposed)
return;
if (Image != null)
{
if (e.Graphics.InterpolationMode != interpolationMode)
e.Graphics.InterpolationMode = interpolationMode;
using (Matrix transform = e.Graphics.Transform)
{
//e.Graphics.ResetTransform();
if (Zoom.X != 1.0 || Zoom.Y != 1.0)
transform.Scale(Zoom.X, Zoom.Y, MatrixOrder.Append);
//if (ImageDisplayLocation.X != 0 || ImageDisplayLocation.Y != 0) //Convert translation back to display pixel unit.
// transform.Translate(ImageDisplayLocation.X / Zoom.X, ImageDisplayLocation.Y / Zoom.Y);
e.Graphics.Transform = transform;
}
}
base.OnPaint(e);
//If you want to draw something over the control in control coordinate, you must first reset the transformation! :D
//e.Graphics.ResetTransform();
//Draw your stuff
}
}
}
代码 Form6_GraphicsTest.cs:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace GraphicsTest
{
public class Form6_GraphicsTest : Form
{
public Form6_GraphicsTest()
{
InitializeComponent();
Bitmap bmp = new Bitmap(@"D:\Test 10x10.8bpp.png");
this.pictureBox21.Image = bmp;
this.pictureBox21.Zoom = new PointF(20,20);
this.ClientSize = new Size(Convert.ToInt32(this.pictureBox21.Zoom.X * bmp.Width) + 30, Convert.ToInt32(this.pictureBox21.Zoom.Y * bmp.Height) + 30);
}
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer components = null;
/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.pictureBox21 = new GraphicsTest.PictureBox2();
((System.ComponentModel.ISupportInitialize)(this.pictureBox21)).BeginInit();
this.SuspendLayout();
//
// pictureBox21
//
this.pictureBox21.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
| System.Windows.Forms.AnchorStyles.Left)
| System.Windows.Forms.AnchorStyles.Right)));
this.pictureBox21.BackColor = System.Drawing.SystemColors.Highlight;
this.pictureBox21.Location = new System.Drawing.Point(12, 12);
this.pictureBox21.Name = "pictureBox21";
this.pictureBox21.Size = new System.Drawing.Size(260, 238);
this.pictureBox21.TabIndex = 0;
this.pictureBox21.TabStop = false;
//
// Form6_GraphicsTest
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.BackColor = System.Drawing.SystemColors.ControlDarkDark;
this.ClientSize = new System.Drawing.Size(284, 262);
this.Controls.Add(this.pictureBox21);
this.Name = "Form6_GraphicsTest";
this.Text = "Form6_GraphicsTest";
((System.ComponentModel.ISupportInitialize)(this.pictureBox21)).EndInit();
this.ResumeLayout(false);
}
#endregion
private PictureBox2 pictureBox21;
}
}