C#绘图放大缩小问题

Question

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

Answer 1

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。

Answer 2

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

Answer 3

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]

Answer 4

        // 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
    }

Answer 5

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

Answer 6

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

Answer 7

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

Answer 8

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

Answer 9

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