【发布时间】：2023-03-25 10:50:01
【问题描述】：
我正在创建一个应用程序，就像在 WPF 中的绘画一样，我想向它添加缩放功能。我将画布作为父级，并将其上的可写位图作为我绘制的子级。当画布尺寸较小时，我在可写位图上绘制很流畅，但是当画布尺寸较大时，放大它，画布尺寸会很大，在这么大的区域上绘制会出现问题。所以我想找到画布的可见区域，这样我就可以顺利地在上面画画了。 请给我一个源代码来找到画布的可见区域。
我已经创建了这个应用程序：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;
using System.Windows;
using System.Windows.Media.Imaging;
using System.Windows.Interop;
namespace MapDesigner.Controls
{
class MapCanvas : Canvas
{
#region Routed Events
public static readonly RoutedEvent SelectedColorChangeEvent = EventManager.RegisterRoutedEvent(
"SelectedColorChange", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(ucToolBox));
public event RoutedEventHandler SelectedColorChange
{
add { AddHandler(SelectedColorChangeEvent, value); }
remove { RemoveHandler(SelectedColorChangeEvent, value); }
}
#endregion
#region Enums
public enum Tool
{
Pencil,
FloodFill,
Eraser,
RectSelect,
Brush,
Part
}
#endregion
WriteableBitmap _wBMP;
Image _dispImg = new Image();
ScaleTransform st = new ScaleTransform();
int canvasHeight, canvasWidth;
double zoomLevel = 1;
Border brdGrid = new Border();
Color cellColor = Colors.Black;
Tool currentTool = Tool.Pencil;
int[,] array;
bool drawing = false;
bool showGrids = true;
public TextBlock tbPos;
public Tool CurrentTool
{
get
{
return currentTool;
}
set
{
currentTool = value;
}
}
public Color CellColor
{
get
{
return cellColor;
}
set
{
cellColor = value;
}
}
public bool GridsVisible
{
get
{
return showGrids;
}
set
{
showGrids = value;
}
}
public MapCanvas()
{
this.Children.Clear();
this.Children.Add(_dispImg);
//st.ScaleX = 1;
//st.ScaleY = 1;
// this.LayoutTransform = st;
}
void Refresh()
{
//canvas = new MapCanvas();
this.Children.Clear();
this.Children.Add(_dispImg);
st.ScaleX = 1;
st.ScaleY = 1;
this.Height = 0;
this.Width = 0;
zoomLevel = 1;
drawing = false;
}
public void LoadBMP(Uri bmpUri)
{
Refresh();
BitmapImage bmi = new BitmapImage(bmpUri);
_wBMP = new WriteableBitmap(bmi);
_dispImg.Source = _wBMP;
this.Height = bmi.Height;
this.Width = bmi.Width;
ShowGrids();
}
public void CreateBMP(int width, int height)
{
Refresh();
_wBMP = new WriteableBitmap(width, height, 96, 96, PixelFormats.Bgr32, BitmapPalettes.WebPalette);
_wBMP.setPixel(Colors.White);
_dispImg.Source = _wBMP;
this.Height = height;
this.Width = width;
ShowGrids();
}
public void CreateNewDesign(Size mapSize)
{
Refresh();
_wBMP = new WriteableBitmap((int)mapSize.Width, (int)mapSize.Width, 96, 96, PixelFormats.Bgr32, BitmapPalettes.WebPalette);
_wBMP.setPixel(Colors.White);
_dispImg.Source = _wBMP;
array = new int[(_wBMP.PixelHeight + 1), (_wBMP.PixelWidth + 1)];
canvasWidth = (int)mapSize.Width;
canvasHeight = (int)mapSize.Height;
this.Height = mapSize.Height;
this.Width = mapSize.Width;
ShowGrids();
}
void ShowGrids()
{
return;
double width = 1;// _tileWidth + _tileMargin;
double height = 1;// _tileHeight + _tileMargin;
double numTileToAccumulate = 16;
Polyline gridCell = new Polyline();
gridCell.Margin = new Thickness(.5);
gridCell.Stroke = Brushes.LightBlue;
gridCell.StrokeThickness = 0.1;
gridCell.Points = new PointCollection(new Point[] { new Point(0, height-0.1),
new Point(width-0.1, height-0.1), new Point(width-0.1, 0) });
VisualBrush gridLines = new VisualBrush(gridCell);
gridLines.TileMode = TileMode.Tile;
gridLines.Viewport = new Rect(0, 0, 1.0 / numTileToAccumulate, 1.0 / numTileToAccumulate);
gridLines.AlignmentX = AlignmentX.Center;
gridLines.AlignmentY = AlignmentY.Center;
VisualBrush outerVB = new VisualBrush();
Rectangle outerRect = new Rectangle();
outerRect.Width = 10.0; //can be any size
outerRect.Height = 10.0;
outerRect.Fill = gridLines;
outerVB.Visual = outerRect;
outerVB.Viewport = new Rect(0, 0,
width * numTileToAccumulate, height * numTileToAccumulate);
outerVB.ViewportUnits = BrushMappingMode.Absolute;
outerVB.TileMode = TileMode.Tile;
this.Children.Remove(brdGrid);
brdGrid = new Border();
brdGrid.Height = this.Height;
brdGrid.Width = this.Width;
brdGrid.Background = outerVB;
this.Children.Add(brdGrid);
}
protected override void OnMouseMove(System.Windows.Input.MouseEventArgs e)
{
base.OnMouseMove(e);
tbPos.Text = (_wBMP.PixelWidth / zoomLevel).ToString() + "," + (_wBMP.PixelHeight / zoomLevel).ToString() + " | " + Math.Ceiling((((Point)e.GetPosition(this)).X) / zoomLevel).ToString() + "," + Math.Ceiling((((Point)e.GetPosition(this)).Y / zoomLevel)).ToString();
if (e.LeftButton == System.Windows.Input.MouseButtonState.Pressed)
{
Point pos = e.GetPosition(this);
int xPos = (int)Math.Ceiling((pos.X) / zoomLevel);
int yPos = (int)Math.Ceiling((pos.Y) / zoomLevel);
int xDraw = (int)Math.Ceiling(pos.X);
int yDraw = (int)Math.Ceiling(pos.Y);
array[xPos, yPos] = 1;
drawing = true;
SetPixelsFromArray((int)zoomLevel);
//for (int i = 0; i < zoomLevel; i++)
//{
// for (int j = 0; j < zoomLevel; j++)
// {
// _wBMP.setPixel(xDraw, yDraw, cellColor);
// _dispImg.Source = _wBMP;
// }
//}
//_wBMP.setPixel(xPos, yPos, cellColor);
//_wBMP.setPixel((int)pos.X, (int)pos.Y, cellColor);
//_dispImg.Source = _wBMP;
}
}
private void SetPixelsFromArray(int ZoomLevel)
{
for (int i = 1; i < _wBMP.PixelWidth / ZoomLevel; i++)
{
for (int j = 1; j < _wBMP.PixelHeight / ZoomLevel; j++)
{
if (array[i, j] == 1)
{
for (int k = 0; k < ZoomLevel; k++)
{
for (int l = 0; l < ZoomLevel; l++)
{
_wBMP.setPixel((int)(i * ZoomLevel + k), (int)(j * ZoomLevel + l), cellColor);
_dispImg.Source = _wBMP;
}
}
}
}
}
}
protected override void OnMouseUp(System.Windows.Input.MouseButtonEventArgs e)
{
//double d= this.ActualHeight;
//Double t =(double) this.GetValue(Canvas.TopProperty);
//double i = Convert.ToDouble(top);
getScreenRect();
if (e.ChangedButton == System.Windows.Input.MouseButton.Right)
{
if (cellColor == Colors.Black)
{
cellColor = Colors.Red;
}
else
{
cellColor = Colors.Black;
}
}
else if (e.ChangedButton == System.Windows.Input.MouseButton.Left)
{
Point pos = e.GetPosition(this);
int xPos = (int)Math.Ceiling((pos.X) / zoomLevel);
int yPos = (int)Math.Ceiling((pos.Y) / zoomLevel);
array[xPos, yPos] = 1;
drawing = true;
SetPixelsFromArray((int)zoomLevel);
//_wBMP.setPixel((int)pos.X, (int)pos.Y, cellColor);
//_dispImg.Source = _wBMP;
}
}
private void getScreenRect()
{
Visual _rootVisual = HwndSource.FromVisual(this).RootVisual;
GeneralTransform transformToRoot = this.TransformToAncestor(_rootVisual);
Rect screenRect = new Rect(transformToRoot.Transform(new Point(0, 0)), transformToRoot.Transform(new Point(this.ActualWidth, this.ActualHeight)));
DependencyObject parent = VisualTreeHelper.GetParent(this);
while (parent != null)
{
Visual visual = parent as Visual;
System.Windows.Controls.Control control = parent as System.Windows.Controls.Control;
if (visual != null && control != null)
{
transformToRoot = visual.TransformToAncestor(_rootVisual);
Point pointAncestorTopLeft = transformToRoot.Transform(new Point(0, 0));
Point pointAncestorBottomRight = transformToRoot.Transform(new Point(control.ActualWidth, control.ActualHeight));
Rect ancestorRect = new Rect(pointAncestorTopLeft, pointAncestorBottomRight);
screenRect.Intersect(ancestorRect);
}
parent = VisualTreeHelper.GetParent(parent);
//}
// at this point screenRect is the bounding rectangle for the visible portion of "this" element
}
// return screenRect;
}
protected override void OnMouseWheel(System.Windows.Input.MouseWheelEventArgs e)
{
base.OnMouseWheel(e);
if (e.Delta > 0)
{
zoomLevel *= 2;
}
else
{
zoomLevel /= 2;
}
if (zoomLevel > 8)
{
zoomLevel = 8;
}
if (zoomLevel <= 1)
{
zoomLevel = 1;
// brdGrid.Visibility = Visibility.Collapsed;
}
else
{
//brdGrid.Visibility = Visibility.Visible;
}
_wBMP = new WriteableBitmap((int)zoomLevel * canvasWidth, (int)zoomLevel * canvasHeight, 96, 96, PixelFormats.Bgr32, BitmapPalettes.WebPalette);
_wBMP.setPixel(Colors.White);
this.Width = zoomLevel * canvasWidth;
this.Height = zoomLevel * canvasHeight;
if (drawing == true)
{
SetPixelsFromArray((int)zoomLevel);
}
//this.InvalidateVisual();
}
internal bool SaveAsBMP(string fileName)
{
return true;
}
}
public static class bitmapextensions
{
public static void setPixel(this WriteableBitmap wbm, Color c)
{
if (!wbm.Format.Equals(PixelFormats.Bgr32))
return;
wbm.Lock();
IntPtr buff = wbm.BackBuffer;
int Stride = wbm.BackBufferStride;
int x = 0;
int y = 0;
for (x = 0; x < wbm.PixelWidth; x++)
{
for (y = 0; y < wbm.PixelHeight; y++)
{
unsafe
{
byte* pbuff = (byte*)buff.ToPointer();
int loc = y * Stride + x * 4;
pbuff[loc] = c.B;
pbuff[loc + 1] = c.G;
pbuff[loc + 2] = c.R;
//pbuff[loc + 3] = c.A;
}
}
}
wbm.AddDirtyRect(new Int32Rect(0, 0, x, y));
wbm.Unlock();
}
public static void setPixel(this WriteableBitmap wbm, int x, int y, Color c)
{
if (y > wbm.PixelHeight - 1 || x > wbm.PixelWidth - 1)
return;
if (y < 0 || x < 0)
return;
if (!wbm.Format.Equals(PixelFormats.Bgr32))
return;
wbm.Lock();
IntPtr buff = wbm.BackBuffer;
int Stride = wbm.BackBufferStride;
unsafe
{
byte* pbuff = (byte*)buff.ToPointer();
int loc = y * Stride + x * 4;
pbuff[loc] = c.B;
pbuff[loc + 1] = c.G;
pbuff[loc + 2] = c.R;
//pbuff[loc + 3] = c.A;
}
wbm.AddDirtyRect(new Int32Rect(x, y, 1, 1));
wbm.Unlock();
}
public static Color getPixel(this WriteableBitmap wbm, int x, int y)
{
if (y > wbm.PixelHeight - 1 || x > wbm.PixelWidth - 1)
return Color.FromArgb(0, 0, 0, 0);
if (y < 0 || x < 0)
return Color.FromArgb(0, 0, 0, 0);
if (!wbm.Format.Equals(PixelFormats.Bgr32))
return Color.FromArgb(0, 0, 0, 0);
IntPtr buff = wbm.BackBuffer;
int Stride = wbm.BackBufferStride;
Color c;
unsafe
{
byte* pbuff = (byte*)buff.ToPointer();
int loc = y * Stride + x * 4;
c = Color.FromArgb(pbuff[loc + 3], pbuff[loc + 2], pbuff[loc + 1], pbuff[loc]);
}
return c;
}
}
}
【问题讨论】：
标签： wpf