RichTextBox CreateCaret 宽度测量 [英] RichTextBox CreateCaret Width Measurement
问题描述
我通过为插入和覆盖模式创建插入符号来扩展富文本框.问题是测量的宽度太宽了.这在较大的字体大小上最为明显.
I'm extending the richtextbox by creating a caret for the insert and overwrite modes. The issue is that the width measured is too wide. This is most noticeable on larger font sizes.
SelectionFont.Height
返回的高度是正确的.有没有类似的 Width 属性?
The height returned from SelectionFont.Height
is correct. Is there no similiar Width property?
如何准确测量指定字符ch
的宽度?谁能举个例子?
How can I measure the width of the specified character ch
accurately? Can anyone provide an example?
下面是转换成C#的代码,下面是VB.NET中的代码:
Below is the code converted to C#, and below that in VB.NET:
using System;
public class RichTextBoxCaret : RichTextBox
{
[DllImport("user32.dll", CharSet=CharSet.Auto)]
private extern static void CreateCaret(IntPtr hWnd, IntPtr hBitmap, int nWidth, int nHeight);
[DllImport("user32.dll", CharSet=CharSet.Auto)]
private extern static void ShowCaret(IntPtr hWnd);
private bool mInsertKeyState = true;
protected override void OnKeyDown(System.Windows.Forms.KeyEventArgs e)
{
base.OnKeyDown(e);
if (e.KeyCode == Keys.Insert)
{
mInsertKeyState = !mInsertKeyState;
}
this.DrawCaret();
}
protected override void OnMouseUp(System.Windows.Forms.MouseEventArgs mevent)
{
base.OnMouseUp(mevent);
this.DrawCaret();
}
public void DrawCaret()
{
Size sz = new Size(0, 0);
if (this.SelectionFont != null)
{
if (!mInsertKeyState && this.SelectionStart < this.TextLength)
{
using (Graphics g = this.CreateGraphics)
{
using (Font f = new Font(this.SelectionFont.FontFamily, this.SelectionFont.Size, this.SelectionFont.Style, GraphicsUnit.Pixel, Convert.ToByte(0), false))
{
char ch = this.Text[this.SelectionStart];
sz.Width = Convert.ToInt32(g.MeasureString(ch, f).Width * this.ZoomFactor);
}
}
}
sz.Height = Convert.ToInt32(this.SelectionFont.Height * this.ZoomFactor);
}
if (!sz.IsEmpty)
{
CreateCaret(this.Handle, IntPtr.Zero, sz.Width, sz.Height);
ShowCaret(this.Handle);
}
}
}
对于 VB.NET:
Public Class RichTextBoxCaret
Inherits RichTextBox
<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Sub CreateCaret(ByVal hWnd As IntPtr, ByVal hBitmap As IntPtr, ByVal nWidth As Integer, ByVal nHeight As Integer)
End Sub
<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Sub ShowCaret(ByVal hWnd As IntPtr)
End Sub
Private mInsertKeyState As Boolean = True
Protected Overrides Sub OnKeyDown(ByVal e As System.Windows.Forms.KeyEventArgs)
MyBase.OnKeyDown(e)
If e.KeyCode = Keys.Insert Then
mInsertKeyState = Not mInsertKeyState
End If
Me.DrawCaret()
End Sub
Protected Overrides Sub OnMouseUp(ByVal mevent As System.Windows.Forms.MouseEventArgs)
MyBase.OnMouseUp(mevent)
Me.DrawCaret()
End Sub
Public Sub DrawCaret()
Dim sz As New Size(0, 0)
If Me.SelectionFont IsNot Nothing Then
If Not mInsertKeyState AndAlso Me.SelectionStart < Me.TextLength Then
Using g As Graphics = Me.CreateGraphics
Using f As New Font(Me.SelectionFont.FontFamily, Me.SelectionFont.Size, Me.SelectionFont.Style, GraphicsUnit.Pixel, CByte(0), False)
Dim ch As Char = Me.Text.Chars(Me.SelectionStart)
sz.Width = CInt(g.MeasureString(ch, f).Width * Me.ZoomFactor)
End Using
End Using
End If
sz.Height = CInt(Me.SelectionFont.Height * Me.ZoomFactor)
End If
If Not sz.IsEmpty Then
CreateCaret(Me.Handle, IntPtr.Zero, sz.Width, sz.Height)
ShowCaret(Me.Handle)
End If
End Sub
End Class
推荐答案
测量宽度已通过使用 GetPositionFromCharIndex
解决.
Measuring the width was resolved by using GetPositionFromCharIndex
.
最终实现:
<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Sub CreateCaret(ByVal hWnd As IntPtr, ByVal hBitmap As IntPtr, ByVal nWidth As Integer, ByVal nHeight As Integer)
End Sub
<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Sub ShowCaret(ByVal hWnd As IntPtr)
End Sub
Private mInsertKeyState As Boolean = True
Protected Overrides Sub OnKeyDown(ByVal e As System.Windows.Forms.KeyEventArgs)
MyBase.OnKeyDown(e)
If e.KeyCode = Keys.Insert Then
mInsertKeyState = Not mInsertKeyState
End If
Me.DrawCaret()
End Sub
Protected Overrides Sub OnMouseUp(ByVal mevent As System.Windows.Forms.MouseEventArgs)
MyBase.OnMouseUp(mevent)
Me.DrawCaret()
End Sub
Public Sub DrawCaret()
Dim nHeight As Integer = 0
Dim nWidth As Integer = 0
If Me.SelectionFont IsNot Nothing Then
nHeight = CInt(Me.SelectionFont.Height * Me.ZoomFactor)
Else
nHeight = CInt(Me.Font.Height * Me.ZoomFactor)
End If
If Not mInsertKeyState AndAlso Me.SelectionStart < Me.TextLength Then
Dim p1 As Point = MyBase.GetPositionFromCharIndex(Me.SelectionStart)
Dim p2 As Point = MyBase.GetPositionFromCharIndex(Me.SelectionStart + 1)
nWidth = p2.X - p1.X
End If
CreateCaret(Me.Handle, IntPtr.Zero, nWidth, nHeight)
ShowCaret(Me.Handle)
End Sub
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