C#绘图放大缩小问题

[cyxcw1]

运用GDI+绘图,比如点画线,点画矩形...
如何实现画出来这些图形的放大缩小功能,还要增加旋转,恢复的功能

[cdglynn]

呵呵，希望你多动动脑筋，本想围观，程序员都不容易，还是给你个代码吧（效率不高)
[code=C#]public class ImageViewer : UserControl
{
public Image Image = null;
// 从一个显示一个现有的Image对象
public void ShowImage(Image image)
{
this.Clear(false);

if (image == null)
{
this.Invalidate();
return;
}

this._image = image;
this._size.Width = image.Width;
this._size.Height = image.Height;

// 创建内存位图
this._memImage = new Bitmap((int)this._size.Width, (int)this._size.Height);
this._memGraphic = Graphics.FromImage(this._memImage);
this._memGraphic.DrawImage(this._image, 0, 0, this._size.Width, this._size.Height);

Image = _image;

this.Invalidate();
}

// 图片的原始大小
public void ZoomNormal()
{
this._size.Height = this._image.Height;
this._size.Width = this._image.Width;
this._anchor.X = 0;
this._anchor.Y = 0;
Invalidate();
}

// 放大图片. factor > 0 为放大, factor < 0 为缩小, =0 不变.
public void Zoom(int factor)
{
if (factor == 0)
return;

int zoomx = 0;
int zoomy = 0;

bool mouseInImage = this._mouse.X > this._anchor.X
&& this._mouse.X < this._anchor.X + this._size.Width
&& this._mouse.Y > this._anchor.Y
&& this._mouse.Y < this._anchor.Y + this._size.Height;

if (factor > 0)
{
zoomx = (int)(this._size.Width * this._delta);
zoomy = (int)(this._size.Height * this._delta);

// 如果鼠标在图片是, 以鼠标为中心放大, 此时调整anchor的位置
// 否则, 则按照窗口大小进行位置调整.
if (mouseInImage)
{
float adjx = (float)(this._mouse.X - this._anchor.X) / (float)this._size.Width;
float adjy = (float)(this._mouse.Y - this._anchor.Y) / (float)this._size.Height;
this._anchor.X -= (int)(adjx * zoomx);
this._anchor.Y -= (int)(adjy * zoomy);
}
this._size.Width = this._size.Width + zoomx;
this._size.Height = this._size.Height + zoomy;
}
else
{

if (this._size.Width < this.Width / 2 && this._size.Height < this.Height / 2)
return;

zoomx = (int)(this._size.Width * this._delta);
zoomy = (int)(this._size.Height * this._delta);

if (mouseInImage)
{
float adjx = (float)(this._mouse.X - this._anchor.X) / (float)this._size.Width;
float adjy = (float)(this._mouse.Y - this._anchor.Y) / (float)this._size.Height;

this._anchor.X += (int)(adjx * zoomx);
this._anchor.Y += (int)(adjy * zoomy);
}
this._size.Width = this._size.Width - zoomx;
this._size.Height = this._size.Height - zoomy;
}

Invalidate();
}

// 居中一个边框.
public void CenterRect(Rectangle rect)
{
this.Invalidate();
}

public void Clear(bool bPaint)
{
if (this._image == null)
return;

this._image = null;

if (this._memGraphic != null)
this._memGraphic.Dispose();
if (this._memImage != null)
this._memImage.Dispose();

this._memImage = null;
this._memGraphic = null;

this._anchor.X = 0;
this._anchor.Y = 0;

this._size.Height = 0;
this._size.Width = 0;

this.HotRect = RectangleF.Empty;

this._moving = false;
}

public RectangleF HotRect
{
get
{
return this._hotRect;
}
set
{
if (this._memImage == null)
return;
if (this.HotRect != RectangleF.Empty) // 回复原图像
{
this._memGraphic.DrawImage(this._image, this._hotRect, this._hotRect, GraphicsUnit.Pixel);
}
this._hotRect = value;
this._memGraphic.FillRectangle(this._hotBrsh, this._hotRect);
this.Invalidate();
}
}

public void CenterRect(RectangleF rect)
{
float x = (rect.Left + rect.Width - this.Width) / -2;
float y = (rect.Top + rect.Height - this.Height) / -2;

ScrollDataInfo(this._anchor.X - x, this._anchor.Y - y);
}

public void CenterAndHotRect(RectangleF rect)
{
if (this.HotRect != RectangleF.Empty) // 回复原图像
{
this._memGraphic.DrawImage(this._image, this._hotRect, this._hotRect, GraphicsUnit.Pixel);
}
this._hotRect = rect;
this._memGraphic.FillRectangle(this._hotBrsh, this._hotRect);
//float x = ( rect.Left + rect.Width - this.Width ) / -2;
//float y = ( rect.Top + rect.Height - this.Height ) / -2;
float x = rect.Left + rect.Width / 2 - this.Width / 2;
float y = rect.Top + rect.Height / 2 - this.Height / 2;
ScrollDataInfo(-x, -y);
this.Invalidate();
}

// 构造函数, 执行初始化工作.
public ImageViewer()
: base()
{
this._backBrush = new TextureBrush(Resource.BITMAP_BACKUP); // 背景画刷
this._anchor = new Point(0, 0); // 起始点坐标
}

protected override void OnPaint(PaintEventArgs e)
{
Rectangle clip = e.ClipRectangle;

if (this._memImage == null)
{
e.Graphics.FillRectangle(this._backBrush, clip);
return;
}

e.Graphics.DrawImage(this._memImage, this._anchor.X, this._anchor.Y,
this._size.Width, this._size.Height);

if (this._anchor.X > 0)
e.Graphics.FillRectangle(this._backBrush, 0, 0, this._anchor.X, Height);

if (this._anchor.Y > 0)
e.Graphics.FillRectangle(this._backBrush, 0, 0, Width, this._anchor.Y);

if (this._anchor.X + this._size.Width < this.Width)
e.Graphics.FillRectangle(
this._backBrush, this._anchor.X + this._size.Width,
Math.Max(this._anchor.Y, 0),
this.Width - this._anchor.X - this._size.Width,
this.Height
);

if (this._anchor.Y + this._size.Height < this.Height)
e.Graphics.FillRectangle(
this._backBrush, Math.Max(this._anchor.X, 0),
this._anchor.Y + this._size.Height,
this.Width,
this.Height - this._anchor.Y - this._size.Height
);
}

// 绘制窗口背景.
protected override void OnPaintBackground(PaintEventArgs e)
{
}

// 鼠标滚轮的事件相应.
protected override void OnMouseWheel(MouseEventArgs e)
{
if (e.Delta == 0)
return;
Zoom(e.Delta);
}

// 鼠标点击事件
protected override void OnMouseDown(MouseEventArgs e)
{
this.Select();
if (e.Button == MouseButtons.Left && this._image != null)
{
this._moving = true;
this._mouse.X = e.X;
this._mouse.Y = e.Y;
}
else
this._moving = false;
}
code]

[cdglynn]

        // 鼠标抬起事件.
        protected override void OnMouseUp(MouseEventArgs e)
        {
            this._moving = false;
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            if (!this._moving)
                return;

            ScrollDataInfo(e.X - this._mouse.X, e.Y - this._mouse.Y);
            this._mouse.X = e.X;
            this._mouse.Y = e.Y;
        }

        // 键按下事件
        protected override void OnKeyDown(KeyEventArgs e)
        {
            if (e.Control)
                this._delta = this.DELTA_MAX;
            else
                this._delta = this.DELTA_MIN;
        }

        // 键弹起事件
        protected override void OnKeyUp(KeyEventArgs e)
        {
            if (this._image == null)  // 没有图像则退出
                return;
            if (e.Control)
                this._delta = this.DELTA_MAX;
            else
                this._delta = this.DELTA_MIN;

            // 翻转
            if (e.KeyCode == Keys.PageDown)
            {
                this._memImage.RotateFlip(RotateFlipType.Rotate90FlipNone);
                SwapDimension();
                Invalidate();
            }

            if (e.KeyCode == Keys.PageUp)
            {
                this._memImage.RotateFlip(RotateFlipType.Rotate270FlipNone);
                SwapDimension();
                Invalidate();
            }

            // 回复原始尺寸
            if (e.KeyCode == Keys.Home)
                this.ZoomNormal();

            // 适合窗口的大小
            if (e.KeyCode == Keys.End)
            {
                this._anchor.X = 0;
                this._anchor.Y = 0;
                this._size.Height = this.Height;
                this._size.Width = this.Width;
                this.Invalidate();
            }


        }

        // 滚动窗口图片
        private void ScrollDataInfo(float DX, float DY)
        {
            DX = CalcDelta(DX, this._anchor.X, this._size.Width, this.Width);
            DY = CalcDelta(DY, this._anchor.Y, this._size.Height, this.Height);

            if (DX == 0 && DY == 0)
                return;

            this.Invalidate();

            this._anchor.X += DX;
            this._anchor.Y += DY;
        }


        // 计算Delta的值
        private float CalcDelta(float delta, float anchor, float size, float extend)
        {
            if (delta == 0)
                return delta;

            if (size > extend)
            {
                if (delta > 0)
                    if (anchor + delta > 0)
                        if (anchor == 0)
                            return 0;
                        else
                            return anchor * -1;
                    else
                        return delta;

                if (anchor + delta < extend - size)
                    if (anchor == extend - size)
                        return 0;
                    else
                        return extend - size - anchor;
                else
                    return delta;
            }
            else
            {
                if (delta > 0)
                    if (anchor + delta > extend - size)
                        if (anchor == extend - size)
                            return 0;
                        else
                            return extend - size - anchor;
                    else
                        return delta;

                if (anchor + delta < 0)
                    if (anchor == 0)
                        return 0;
                    else
                        return anchor * -1;
                else
                    return delta;
            }
        }

        // 翻转图像的长宽
        private void SwapDimension()
        {
            float i = this._size.Height;
            this._size.Height = this._size.Width;
            this._size.Width = i;
        }

        private TextureBrush _backBrush = null;            // 背景画刷
        private PointF _anchor;                                        // 当前图片的左上角坐标
        private PointF _mouse;                                        // 当前鼠标的位置. 
        private bool _moving = false;                              // 正在移动图像
        private float _delta = 0.1F;                                 // 放大速度.
        private SizeF _size = Size.Empty;                         // 图像的大小
        private Image _image = null;                             // 显示的图片
        private RectangleF _hotRect;                                     // 当前的高亮矩形.
        private Brush _hotBrsh = new SolidBrush(Color.FromArgb(50, Color.Blue));

        private Image _memImage;
        private Graphics _memGraphic;

        private float DELTA_MAX = 0.3F;                          // 最大缩放比
        private float DELTA_MIN = 0.1F;                           // 最小缩放比
    }

[gavinmark]

学习了。UP

[mabiJay]

[Quote=引用 7 楼 cdglynn 的回复:]
C# code

// 鼠标抬起事件.
protected override void OnMouseUp(MouseEventArgs e)
{
this._moving = false;
}

protected override void OnMouseMove(Mouse……
[/Quote]


学习 ... ...

[zerodegrees]

[Quote=引用 7 楼 cdglynn 的回复:]
C# code

// 鼠标抬起事件.
protected override void OnMouseUp(MouseEventArgs e)
{
this._moving = false;
}

protected override void OnMouseMove(Mouse……
[/Quote]
好长啊。。。

[Fry_cici]

http://www.cnblogs.com/cloudgamer/archive/2010/08/16/ImageTrans.html
看看这个 功能很全的

[Fry_cici]

http://www.cnblogs.com/cloudgamer/archive/2010/04/14/ImageZoom_ext.html

[cyxcw1]

谢谢大家的回答了,我想那些代码会对我有用的
我仔细看看...嘿嘿

[xuzhx]

懒人！ 非常简单的坐标计算而已，就是不愿动脑筋！

[x89652]

不太会这放面的 待请教

[wjq]

1: 矢量绘图，记录点的相对坐标，根据需要的尺寸绘制
2：绘制到一个内存Image上，然后复制图片到另一个Image上，同时指定目标尺寸和缩放方式。

[duanzhi1984]

这个没用过，期待高手来啊。。

[gaomeng320]

会有答案吗

[cyxcw1]

1楼
能说的更清楚些吗,我刚开始用GDI+,希望有个例子

我看BASIC有这个功能,但是我现在还没学

[cyxcw1]

求解答...

[zhuimeng11025]

你是想做画图程序吧
http://www.codeproject.com/KB/cs/DrawToolsRedux.aspx
看下这段源码
相信对你有帮助了
有问题可以互相探讨

[ctr54188]

看看学习了

[cyxcw1]

public class ImageViewer : UserControl
  {
  public Image Image = null;
  // 从一个显示一个现有的Image对象
  public void ShowImage(Image image)
  {
  this.Clear(false);

  if (image == null)
  {
  this.Invalidate();
  return;
  }

  this._image = image;
  this._size.Width = image.Width;
  this._size.Height = image.Height;

  // 创建内存位图
  this._memImage = new Bitmap((int)this._size.Width, (int)this._size.Height);
  this._memGraphic = Graphics.FromImage(this._memImage);
  this._memGraphic.DrawImage(this._image, 0, 0, this._size.Width, this._size.Height);

  Image = _image;

  this.Invalidate();
  }

  // 图片的原始大小
  public void ZoomNormal()
  {
  this._size.Height = this._image.Height;
  this._size.Width = this._image.Width;
  this._anchor.X = 0;
  this._anchor.Y = 0;
  Invalidate();
  }

  // 放大图片. factor > 0 为放大, factor < 0 为缩小, =0 不变.
  public void Zoom(int factor)
  {
  if (factor == 0)
  return;

  int zoomx = 0;
  int zoomy = 0;

  bool mouseInImage = this._mouse.X > this._anchor.X
  && this._mouse.X < this._anchor.X + this._size.Width
  && this._mouse.Y > this._anchor.Y
  && this._mouse.Y < this._anchor.Y + this._size.Height;

  if (factor > 0)
  {
  zoomx = (int)(this._size.Width * this._delta);
  zoomy = (int)(this._size.Height * this._delta);

  // 如果鼠标在图片是, 以鼠标为中心放大, 此时调整anchor的位置
  // 否则, 则按照窗口大小进行位置调整.
  if (mouseInImage)
  {
  float adjx = (float)(this._mouse.X - this._anchor.X) / (float)this._size.Width;
  float adjy = (float)(this._mouse.Y - this._anchor.Y) / (float)this._size.Height;
  this._anchor.X -= (int)(adjx * zoomx);
  this._anchor.Y -= (int)(adjy * zoomy);
  }
  this._size.Width = this._size.Width + zoomx;
  this._size.Height = this._size.Height + zoomy;
  }
  else
  {

  if (this._size.Width < this.Width / 2 && this._size.Height < this.Height / 2)
  return;

  zoomx = (int)(this._size.Width * this._delta);
  zoomy = (int)(this._size.Height * this._delta);

  if (mouseInImage)
  {
  float adjx = (float)(this._mouse.X - this._anchor.X) / (float)this._size.Width;
  float adjy = (float)(this._mouse.Y - this._anchor.Y) / (float)this._size.Height;

  this._anchor.X += (int)(adjx * zoomx);
  this._anchor.Y += (int)(adjy * zoomy);
  }
  this._size.Width = this._size.Width - zoomx;
  this._size.Height = this._size.Height - zoomy;
  }

  Invalidate();
  }

  // 居中一个边框.
  public void CenterRect(Rectangle rect)
  {
  this.Invalidate();
  }

  public void Clear(bool bPaint)
  {
  if (this._image == null)
  return;

  this._image = null;

  if (this._memGraphic != null)
  this._memGraphic.Dispose();
  if (this._memImage != null)
  this._memImage.Dispose();

  this._memImage = null;
  this._memGraphic = null;

  this._anchor.X = 0;
  this._anchor.Y = 0;

  this._size.Height = 0;
  this._size.Width = 0;

  this.HotRect = RectangleF.Empty;

  this._moving = false;
  }

  public RectangleF HotRect
  {
  get
  {
  return this._hotRect;
  }
  set
  {
  if (this._memImage == null)
  return;
  if (this.HotRect != RectangleF.Empty) // 回复原图像
  {
  this._memGraphic.DrawImage(this._image, this._hotRect, this._hotRect, GraphicsUnit.Pixel);
  }
  this._hotRect = value;
  this._memGraphic.FillRectangle(this._hotBrsh, this._hotRect);
  this.Invalidate();
  }
  }

  public void CenterRect(RectangleF rect)
  {
  float x = (rect.Left + rect.Width - this.Width) / -2;
  float y = (rect.Top + rect.Height - this.Height) / -2;

  ScrollDataInfo(this._anchor.X - x, this._anchor.Y - y);
  }

  public void CenterAndHotRect(RectangleF rect)
  {
  if (this.HotRect != RectangleF.Empty) // 回复原图像
  {
  this._memGraphic.DrawImage(this._image, this._hotRect, this._hotRect, GraphicsUnit.Pixel);
  }
  this._hotRect = rect;
  this._memGraphic.FillRectangle(this._hotBrsh, this._hotRect);
  //float x = ( rect.Left + rect.Width - this.Width ) / -2;
  //float y = ( rect.Top + rect.Height - this.Height ) / -2;
  float x = rect.Left + rect.Width / 2 - this.Width / 2;
  float y = rect.Top + rect.Height / 2 - this.Height / 2;
  ScrollDataInfo(-x, -y);
  this.Invalidate();
  }

  // 构造函数, 执行初始化工作.
  public ImageViewer()
  : base()
  {
  this._backBrush = new TextureBrush(Resource.BITMAP_BACKUP); // 背景画刷
  this._anchor = new Point(0, 0); // 起始点坐标
  }

  protected override void OnPaint(PaintEventArgs e)
  {
  Rectangle clip = e.ClipRectangle;

  if (this._memImage == null)
  {
  e.Graphics.FillRectangle(this._backBrush, clip);
  return;
  }

  e.Graphics.DrawImage(this._memImage, this._anchor.X, this._anchor.Y,
  this._size.Width, this._size.Height);

  if (this._anchor.X > 0)
  e.Graphics.FillRectangle(this._backBrush, 0, 0, this._anchor.X, Height);

  if (this._anchor.Y > 0)
  e.Graphics.FillRectangle(this._backBrush, 0, 0, Width, this._anchor.Y);

  if (this._anchor.X + this._size.Width < this.Width)
  e.Graphics.FillRectangle(
  this._backBrush, this._anchor.X + this._size.Width,
  Math.Max(this._anchor.Y, 0),
  this.Width - this._anchor.X - this._size.Width,
  this.Height
  );

  if (this._anchor.Y + this._size.Height < this.Height)
  e.Graphics.FillRectangle(
  this._backBrush, Math.Max(this._anchor.X, 0),
  this._anchor.Y + this._size.Height,
  this.Width,
  this.Height - this._anchor.Y - this._size.Height
  );
  }

  // 绘制窗口背景.
  protected override void OnPaintBackground(PaintEventArgs e)
  {
  }

  // 鼠标滚轮的事件相应.
  protected override void OnMouseWheel(MouseEventArgs e)
  {
  if (e.Delta == 0)
  return;
  Zoom(e.Delta);
  }

  // 鼠标点击事件
  protected override void OnMouseDown(MouseEventArgs e)
  {
  this.Select();
  if (e.Button == MouseButtons.Left && this._image != null)
  {
  this._moving = true;
  this._mouse.X = e.X;
  this._mouse.Y = e.Y;
  }
  else
  this._moving = false;
  }

自己看看,这样方便

[兔子-顾问]

简单点，你看msdn中Graphics.DrawImage就可以了。
复杂的就是用坐标转换。多种方式。你如果学GDI+，最不能错过的就是这个GDI+全面的范例了。
http://download.csdn.net/source/2090762