这是滚动事件
int countver = 0;
int counthor = 0;
Image newImage;
private void trackBar2_Scroll(object sender, EventArgs e)
{
if (files != null && files.Length > 0)
{
newImage = Image.FromFile(files[files.Length - 1]);
float imghorizontal = newImage.HorizontalResolution;
float imgvertical = newImage.VerticalResolution;
if (trackBar2.Value < trackBar2.Maximum)
{
countver += 100;
counthor += 100;
}
if (trackBar2.Value == trackBar2.Maximum)
{
countver += 100;
counthor += 100;
}
pictureBox1.Image = ResizeImage(files[files.Length - 1], (int)imghorizontal + counthor, (int)imgvertical + countver);
label15.Text = (int)imghorizontal + counthor.ToString() + "," + (int)imgvertical + countver.ToString();
label15.Visible = true;
}
}
这是调整图像大小的方法
private static Bitmap ResizeImage(String filename, int maxWidth, int maxHeight)
{
using (Image originalImage = Image.FromFile(filename))
{
//Caluate new Size
int newWidth = originalImage.Width;
int newHeight = originalImage.Height;
double aspectRatio = (double)originalImage.Width / (double)originalImage.Height;
if (aspectRatio <= 1 && originalImage.Width > maxWidth)
{
newWidth = maxWidth;
newHeight = (int)Math.Round(newWidth / aspectRatio);
}
else if (aspectRatio > 1 && originalImage.Height > maxHeight)
{
newHeight = maxHeight;
newWidth = (int)Math.Round(newHeight * aspectRatio);
}
if (newWidth >= 0 && newHeight >= 0)
{
Bitmap newImage = new Bitmap(newWidth, newHeight);
using (Graphics g = Graphics.FromImage(newImage))
{
//--Quality Settings Adjust to fit your application
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
g.DrawImage(originalImage, 0, 0, newImage.Width, newImage.Height);
return newImage;
}
}
return null;
}
}
问题是当我向上或向下移动卷轴时，需要1-3秒才能完成图像处理。如果我将滚动更快地移动到另一个值，它会采取更多（另一个值，我的意思是我试图将滑块从开始移动到结束程序挂起）。
这是form1代码，我使用后台工作程序来更改硬盘上的图像大小。整个想法是让用户预览图像的样子，然后如果他确定它足够好，他点击一个启动背景工作者的按钮。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Net;
namespace Images_Batch_Resize
{
public partial class Form1 : Form
{
OpenFileDialog openFileDialog1;
string[] files;
string directoryPath;
public Form1()
{
InitializeComponent();
label6.Visible = false;
label7.Visible = false;
label8.Visible = false;
label9.Visible = false;
label10.Visible = false;
label12.Visible = false;
label15.Visible = false;
openFileDialog1 = new OpenFileDialog();
trackBar2.Minimum = 0;
trackBar2.Maximum = 20;
}
private void changeWorkingDirectoryToolStripMenuItem_Click(object sender, EventArgs e)
{
openFileDialog1.Filter = "BMP|*.bmp|GIF|*.gif|JPG|*.jpg;*.jpeg|PNG|*.png|TIFF|*.tif;*.tiff|"
+ "All Graphics Types|*.bmp;*.jpg;*.jpeg;*.png;*.tif;*.tiff";
//openFileDialog1.InitialDirectory = @"c:\";
openFileDialog1.RestoreDirectory = true;
openFileDialog1.Multiselect = true;
DialogResult result = openFileDialog1.ShowDialog();
if (result == DialogResult.OK)
{
files = openFileDialog1.FileNames;
try
{
if (files.Length > 0)
{
label6.Text = files.Length.ToString();
label6.Visible = true;
directoryPath = Path.GetDirectoryName(files[0]);
label12.Text = directoryPath;
label12.Visible = true;
pictureBox2.Load(files[0]);
pictureBox1.Load(files[0]);
trackBar1.Minimum = 0;
trackBar1.Maximum = files.Length - 1;
}
}
catch (IOException)
{
}
}
}
private void beginOperationToolStripMenuItem_Click(object sender, EventArgs e)
{
if (files.Length > 0)
{
backgroundWorker1.RunWorkerAsync();
}
}
private static Bitmap ResizeImage(String filename, int maxWidth, int maxHeight)
{
using (Image originalImage = Image.FromFile(filename))
{
//Caluate new Size
int newWidth = originalImage.Width;
int newHeight = originalImage.Height;
double aspectRatio = (double)originalImage.Width / (double)originalImage.Height;
if (aspectRatio <= 1 && originalImage.Width > maxWidth)
{
newWidth = maxWidth;
newHeight = (int)Math.Round(newWidth / aspectRatio);
}
else if (aspectRatio > 1 && originalImage.Height > maxHeight)
{
newHeight = maxHeight;
newWidth = (int)Math.Round(newHeight * aspectRatio);
}
if (newWidth >= 0 && newHeight >= 0)
{
Bitmap newImage = new Bitmap(newWidth, newHeight);
using (Graphics g = Graphics.FromImage(newImage))
{
//--Quality Settings Adjust to fit your application
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
g.DrawImage(originalImage, 0, 0, newImage.Width, newImage.Height);
return newImage;
}
}
return null;
}
}
int countver = 0;
int counthor = 0;
Image newImage;
private void trackBar2_Scroll(object sender, EventArgs e)
{
if (files != null && files.Length > 0)
{
newImage = Image.FromFile(files[files.Length - 1]);
float imghorizontal = newImage.HorizontalResolution;
float imgvertical = newImage.VerticalResolution;
if (trackBar2.Value < trackBar2.Maximum)
{
countver += 100;
counthor += 100;
}
if (trackBar2.Value == trackBar2.Maximum)
{
countver += 100;
counthor += 100;
}
pictureBox1.Image = ResizeImage(files[files.Length - 1], (int)imghorizontal + counthor, (int)imgvertical + countver);
label15.Text = (int)imghorizontal + counthor.ToString() + "," + (int)imgvertical + countver.ToString();
label15.Visible = true;
}
}
private void trackBar1_Scroll(object sender, EventArgs e)
{
pictureBox1.Load(files[trackBar1.Value]);
pictureBox2.Load(files[trackBar1.Value]);
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
try
{
BackgroundWorker worker = sender as BackgroundWorker;
int counter = 0;
int percentage = 0;
foreach (string file in files)
{
Bitmap bmp1 = new Bitmap(ResizeImage(file, 300, 300));
string resizedfilename = Path.Combine(directoryPath, Path.GetFileNameWithoutExtension(file) + "_resized.jpg");
bmp1.Save(resizedfilename);
bmp1.Dispose();
counter++;
percentage = counter * 100 / files.Length;
worker.ReportProgress(percentage);
}
}
catch(Exception err)
{
string ttt = err.ToString();
}
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
}
int oldValue = 0;
private void trackBar2_ValueChanged(object sender, EventArgs e)
{
if ((sender as TrackBar).Value >= oldValue)
{
}
else
{
}
oldValue = (sender as TrackBar).Value;
}
}
}