我正在尝试对字符串进行一些命中测试(我想从 x 偏移量获取字符索引),但我遇到了测量字符串的问题。
这本质上是我正在使用的代码
StringFormat sf = new StringFormat(StringFormatFlags.MeasureTrailingSpaces | StringFormatFlags.NoWrap | StringFormatFlags.LineLimit);
e.Graphics.MeasureString("test string", this.Font, new SizeF(xHitTestPosition, this.Font.Height), sf, out charFitted, out linesFilled);
charFitted 的值应设置为它可以在其给定的大小内容纳的字符数(我根据我尝试进行测试的点为其指定一个大小)。
这可以正常工作,直到该区域足够大以容纳“测试”字符串。此时 charFitted 从 3 ('tes') 跳转到 8 ('test')。它基本上总是包含所有空白,无论它被赋予了多少空间。
我尝试过修改 StringFormat 设置,但似乎没有什么帮助......
我在下面添加了一个测试应用程序来演示这一点
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 WindowsFormsApplication2
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
trackBar1.Maximum = this.ClientRectangle.Width;
}
protected override void OnPaint(PaintEventArgs e)
{
string sample = "abc def";
int charFitted, linesFilled;
e.Graphics.DrawString(sample, this.Font, Brushes.Black, PointF.Empty);
e.Graphics.DrawLine(Pens.Red, trackBar1.Value, 0, trackBar1.Value, 100);
StringFormat sf = new StringFormat(StringFormatFlags.MeasureTrailingSpaces | StringFormatFlags.NoWrap | StringFormatFlags.LineLimit);
sf.Trimming = StringTrimming.Character;
e.Graphics.MeasureString(sample, this.Font, new SizeF(trackBar1.Value, this.Font.Height), sf, out charFitted, out linesFilled);
textBox1.Text = "[" + sample.Substring(0, charFitted) + "]";
base.OnPaint(e);
}
private void trackBar1_Scroll(object sender, EventArgs e)
{
Invalidate();
}
/// <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.trackBar1 = new System.Windows.Forms.TrackBar();
this.textBox1 = new System.Windows.Forms.TextBox();
((System.ComponentModel.ISupportInitialize)(this.trackBar1)).BeginInit();
this.SuspendLayout();
//
// trackBar1
//
this.trackBar1.Location = new System.Drawing.Point(13, 184);
this.trackBar1.Name = "trackBar1";
this.trackBar1.Size = new System.Drawing.Size(259, 45);
this.trackBar1.TabIndex = 0;
this.trackBar1.Scroll += new System.EventHandler(this.trackBar1_Scroll);
//
// textBox1
//
this.textBox1.Location = new System.Drawing.Point(22, 229);
this.textBox1.Name = "textBox1";
this.textBox1.Size = new System.Drawing.Size(237, 20);
this.textBox1.TabIndex = 1;
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(284, 261);
this.Controls.Add(this.textBox1);
this.Controls.Add(this.trackBar1);
this.Name = "Form1";
this.Text = "Form1";
this.Load += new System.EventHandler(this.Form1_Load);
((System.ComponentModel.ISupportInitialize)(this.trackBar1)).EndInit();
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
private System.Windows.Forms.TrackBar trackBar1;
private System.Windows.Forms.TextBox textBox1;
}
}
问题在于“abc”和“abc”的长度相同。由于您没有打印出尾随空格,因此图形表示形式是相同的。 我会在末尾添加一个字符,然后测量字符串并删除添加字符的长度。
将你的 OnPaint 切换到这个,它似乎可以工作:
protected override void OnPaint(PaintEventArgs e) {
string sample = "abc def";
e.Graphics.DrawString(sample, this.Font, Brushes.Black, PointF.Empty);
e.Graphics.DrawLine(Pens.Red, trackBar1.Value, 0, trackBar1.Value, 100);
StringFormat sf = new StringFormat(StringFormatFlags.MeasureTrailingSpaces | StringFormatFlags.NoWrap | StringFormatFlags.LineLimit);
sf.Trimming = StringTrimming.Character;
var underscoreWidth = e.Graphics.MeasureString("_", this.Font).Width;
for (int i = 0; i < sample.Length; i++) {
var s = sample.Substring(0, i + 1) + "_";
var size = e.Graphics.MeasureString(s, this.Font).Width - underscoreWidth;
if (size > trackBar1.Value) {
if (s.Length > 0) {
var ok = s.Substring(0, s.Length - 2);
textBox1.Text = "[" + ok + "]";
base.OnPaint(e);
return;
}
}
}
textBox1.Text = "[" + sample + "]";
base.OnPaint(e);
}
我真的不喜欢这个解决方案,但到目前为止它是我唯一有效的解决方案。它基于 @FSDaniel 的解决方案,但我注意到,即使您将相同的
Graphics.MeasureString
传递给它们,StringFormat
和 Graphics.DrawString 的结果也会漂移。
我使用
TextRenderer
和 TextFormatFlags.TextBoxControl
标志集成功实现的唯一一致测量。
这是一个令人讨厌的解决方案,可以通过寻找结果来稍微改进(性能方面),即从字符串的中间开始,如果它太大,请尝试字符串的 3/4,如果太小,请尝试 5/8等等,直到得到结果。
这远不是最好的解决方案,所以如果有人有更好的解决方案,请发布!
protected override void OnPaint(PaintEventArgs e)
{
string sample = "abc defXXXXXXXXXXXXiiiiiiiX";
TextFormatFlags flags = TextFormatFlags.NoPadding | TextFormatFlags.TextBoxControl | TextFormatFlags.SingleLine | TextFormatFlags.NoPrefix;
TextRenderer.DrawText(e.Graphics, sample, this.Font, Point.Empty, Color.Black, flags);
e.Graphics.DrawLine(Pens.Red, trackBar1.Value, 0, trackBar1.Value, 100);
string measuredString = sample;
for (int i = 0; i < sample.Length; i++)
{
Size size = TextRenderer.MeasureText(e.Graphics, sample.Substring(0, i+1), this.Font, new Size(10000000, 1000000), flags);
if (size.Width > trackBar1.Value)
{
textBox1.Text = "[" + sample.Substring(0,i+1) + "]";
break;
}
}
base.OnPaint(e);
}