加载图片处理的问题代码
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Dim videoBitmap As Bitmap = Image.FromFile("c:\aa.bmp")
Dim gg As Graphics = Graphics.FromImage(videoBitmap)
gg.DrawLine(Pens.Red, 0, 0, 200, 100)
PictureBox1.Image = videoBitmap
'GC.Collect()
End Sub
以上代码大概每秒运行20次左右。c:\aa.bmp 文件大小是5M 运行的时候内存一直在增加，增加200多M 后 回归正常，然后继续增加。
不使用gc.collect 语句，还有什么写法可以解决？
--------------------编程问答-------------------- 如果图片是固定的，那么在开始前先载入图片，每次画的时候就不需要从硬盘里读取，速度更快。
因为你每次都new出来一个bitmap，所以每次都会为图片开辟一块内存，当垃圾回收周期没到时，则内存会一直增加。
如果能重复利用一张图片，则可以解决内存增加的问题，否则就只能GC.Collect了 --------------------编程问答-------------------- 图片是变化的。
picturbox1 得到处理后的图片后 如何释放 bitmap？
PictureBox1.Image = Image.FromFile("c:\aa.bmp") 就反复执行这句，内存加的一塌糊涂 --------------------编程问答--------------------
gg也需要Dispose --------------------编程问答-------------------- gg.Dipose();
videoBitmap.Dipose(); --------------------编程问答--------------------
videobitmap.dispose 是错的。 --------------------编程问答--------------------
你的bitmap被picturebox引用了，不能dispose --------------------编程问答--------------------
/// <summary>--------------------编程问答-------------------- --------------------编程问答-------------------- 顶起来 --------------------编程问答-------------------- private _B as bitmap
/// 图片处理类
/// </summary>
public class Image
{
/// <summary>
/// 加图片水印
/// </summary>
/// <param name="filePath">原图片路径</param>
/// <param name="waterPath">水印图片路径</param>
/// <returns>加完水印后的文件名</returns>
public static string WaterPic(string filePath, string waterPath)
{
string dir = System.IO.Path.GetDirectoryName(filePath);
string filename = System.IO.Path.GetFileName(filePath);
string ext = System.IO.Path.GetExtension(filePath);
if (ext != ".bmp" && ext != ".jpg" && ext != ".png") return "";
//加图片水印
System.Drawing.Image image = System.Drawing.Image.FromFile(filePath);
System.Drawing.Image copyImage = System.Drawing.Image.FromFile(waterPath);
Graphics g = Graphics.FromImage(image);
g.DrawImage(copyImage, new Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
g.Dispose();
copyImage.Dispose();
//保存加水印过后的图片,删除原始图片
string newPath = dir + "\\w_" + filename;
if (ext == ".jpg") image.Save(newPath, System.Drawing.Imaging.ImageFormat.Jpeg);
if (ext == ".bmp") image.Save(newPath, System.Drawing.Imaging.ImageFormat.Bmp);
if (ext == ".png") image.Save(newPath, System.Drawing.Imaging.ImageFormat.Png);
image.Dispose();
return "\\w_" + filename;
}
/// 生成缩略图
/// </summary>
/// <param name="originalImagePath">源图路径（物理路径）</param>
///<param name="thumbnailPath">缩略图路径（物理路径）</param>
///<param name="width">缩略图宽度</param>
///<param name="height">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
{
System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case "HW"://指定高宽缩放（可能变形）
break;
case "W"://指定宽，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case "H"://指定高，宽按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case "Cut"://指定高宽裁减（不变形）
if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
{
oh = originalImage.Height;
ow = originalImage.Height * towidth / toheight;
y = 0;
x = (originalImage.Width - ow) / 2;
}
else
{
ow = originalImage.Width;
oh = originalImage.Width * height / towidth;
x = 0;
y = (originalImage.Height - oh) / 2;
}
break;
default:
break;
}
//新建一个bmp图片
System.Drawing.Image bitmap = new System.Drawing.Bitmap(width, height);
//新建一个画板
Graphics g = System.Drawing.Graphics.FromImage(bitmap);
//设置高质量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//设置高质量,低速度呈现平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//清空画布并以透明背景色填充
g.Clear(Color.Transparent);
//在指定位置并且按指定大小绘制原图片的指定部分
g.DrawImage(originalImage, new Rectangle(0, 0, height, height), new Rectangle(x, y, ow, oh), GraphicsUnit.Pixel);
try
{ //以jpg格式保存缩略图
bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (System.Exception e) { throw e; }
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
}
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
if _B isnot nothing then _B.Dispose()
_B= new bitmap("c:\aa.bmp")
Dim gg As Graphics = Graphics.FromImage(videoBitmap)
gg.DrawLine(Pens.Red, 0, 0, 200, 100)
PictureBox1.Image = videoBitmap
End Sub
补充：.NET技术 , VB.NET
