如何限制在面板内拖动图像
本文关键字：拖动 图像 何限制 | 更新日期: 2023-09-27 18:16:40
晚上好。我目前正在开发一个交互式地图编辑器。我试图通过使用以下代码来防止地图图像被拖出视图
if (currentPosition.X > 0)
currentPosition.X = 0;
else if (currentPosition.X < -mapSize.Width + Size.Width )
currentPosition.X = -mapSize.Width + Size.Width ;
if (currentPosition.Y > 0)
currentPosition.Y = 0;
else if (currentPosition.Y < -mapSize.Height + Size.Height)
currentPosition.Y = -mapSize.Height + Size.Height;
但是我不能把它拖到限制大小地图大小。currentPosition对应于图像的左上角位置。下面是类
的完整代码namespace GameMaps
{
public class MapPanel : Panel
{
private Bitmap shownMap = null;
private Point mapLocation;
private Size mapSize;
private bool dragging;
private Point currentPosition;
//private Point newPosition;
private Point initialPosition;
private Point initialMousePosition;
private Form1 parentForm;
public MapPanel(Form1 parentForm) : base()
{
this.DoubleBuffered = true;
this.parentForm = parentForm;
}
public MapPanel(Panel targetPanel) : this(new Form1())
{
}
public void ShowMap(Map map)
{
if (map == null) return;
shownMap = map.MapTexture;
mapLocation = new Point(0, 0);
mapSize = shownMap.Size;
currentPosition = new Point();
initialPosition = new Point();
initialMousePosition = new Point(); //mapLocation;
}
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.PageUnit = GraphicsUnit.Pixel;
e.Graphics.PageScale = 1.0F;
// base.OnPaint(e);
if (shownMap == null)
{
base.OnPaint(e);
return;
}
e.Graphics.DrawImage(shownMap, currentPosition.X, currentPosition.Y);
}
protected override void OnMouseDown(MouseEventArgs e)
{
// base.OnMouseDown(e);
if (shownMap == null)
{
base.OnMouseDown(e);
return;
}
if (dragging)
{
dragging = false;
return;
}
else dragging = true;
initialPosition.X = currentPosition.X;
initialPosition.Y = currentPosition.Y;
initialMousePosition = e.Location;
}
protected override void OnMouseMove(MouseEventArgs e)
{
/*parentForm.label7.Text = currentPosition.X.ToString();
parentForm.label8.Text = currentPosition.Y.ToString();
parentForm.label9.Text = mapSize.Width.ToString();
parentForm.label10.Text = mapSize.Height.ToString();
parentForm.label11.Text = Size.Width.ToString();
parentForm.label12.Text = Size.Width.ToString();*/
//base.OnMouseMove(e);
if (!dragging) return;
currentPosition.X = e.X - initialMousePosition.X + initialPosition.X;
currentPosition.Y = e.Y - initialMousePosition.Y + initialPosition.Y;
if (currentPosition.X > 0)
currentPosition.X = 0;
else if (currentPosition.X < -mapSize.Width + Size.Width )
currentPosition.X = -mapSize.Width + Size.Width ;
if (currentPosition.Y > 0)
currentPosition.Y = 0;
else if (currentPosition.Y < -mapSize.Height + Size.Height)
currentPosition.Y = -mapSize.Height + Size.Height;
//if (currentPosition.X + mapSize.Width < this.Size.Width)
// currentPosition.X = this.Size.Width - mapSize.Width;
Invalidate();
// (e.X - initialPosition.X + xinit, e.Y - init_loc.Y + yinit);
}
protected override void OnMouseLeave(EventArgs e)
{
// base.OnMouseLeave(e);
dragging = false;
// F*! if I hold the mouse down this does not work
}
protected override void OnMouseUp(MouseEventArgs e)
{
//base.OnMouseUp(e);
dragging = false;
}
}
}
嗯，似乎没有坏的逻辑，除了我使用面板的大小，而不是它的DisplayRectangle(大小)。宽度== DisplayRectangle.Width-2)。整个问题是，我使用的图像是从Photoshop中导出的，分辨率为72dpi，而不是96dpi:相同大小，但使用DrawImage时，它们被放大了。这是我的解决方案。仍然有这个要纠正，但这是关于我原来的问题的解决方案。还有一些变量名也被改变了。
namespace GameMaps
{
public class MapPanel : Panel
{
private Map sourceMap;
private Bitmap mapTexture;
private Size mapSize;
private Point mapPosition;
private float dpiX, dpiY;
private Point initialPosition;
private Point initialMousePosition;
private bool dragging;
/* Constructors */
public MapPanel() : base()
{
this.DoubleBuffered = true;
this.sourceMap = null;
this.dpiX = 96.0F; this.dpiY = 96.0F; // For now, this Application won't be DPI aware
}
public MapPanel(Panel targetPanel) : this()
{
// TO DO
}
/* Show a Map */
public void ShowMap(Map map)
{
if (map == null)
return;
sourceMap = map;
mapTexture = new Bitmap(map.MapTexture);
mapTexture.SetResolution(dpiX, dpiY);
mapSize = mapTexture.Size; // ?
mapPosition = new Point(0, 0);
}
protected override void OnPaint(PaintEventArgs e)
{
// base.OnPaint(e);
e.Graphics.PageUnit = GraphicsUnit.Pixel; // ?
e.Graphics.PageScale = 1.0F; // ?
if (sourceMap == null)
{
base.OnPaint(e);
return;
}
e.Graphics.DrawImage(mapTexture, mapPosition.X, mapPosition.Y);
}
protected override void OnMouseDown(MouseEventArgs e)
{
// base.OnMouseDown(e);
if (sourceMap == null)
{
base.OnMouseDown(e);
return;
}
if (dragging)
{
dragging = false;
return;
}
else dragging = true;
initialPosition.X = mapPosition.X;
initialPosition.Y = mapPosition.Y;
initialMousePosition.X = e.Location.X;
initialMousePosition.Y = e.Location.Y;
}
protected override void OnMouseMove(MouseEventArgs e)
{
//base.OnMouseMove(e);
if (!dragging) return;
mapPosition.X = e.X - initialMousePosition.X + initialPosition.X;
mapPosition.Y = e.Y - initialMousePosition.Y + initialPosition.Y;
if (mapPosition.X > 0)
mapPosition.X = 0;
else if (mapPosition.X < DisplayRectangle.Width - mapSize.Width)
mapPosition.X = DisplayRectangle.Width - mapSize.Width;
if (mapPosition.Y > 0)
mapPosition.Y = 0;
else if (mapPosition.Y < DisplayRectangle.Height - mapSize.Height)
mapPosition.Y = DisplayRectangle.Height - mapSize.Height;
Invalidate(); // Force Repaint
}
protected override void OnMouseLeave(EventArgs e)
{
// base.OnMouseLeave(e);
dragging = false;
// TO DO: Correct this
}
protected override void OnMouseUp(MouseEventArgs e)
{
//base.OnMouseUp(e);
dragging = false;
}
}
}