实现思路
制作一个用户头像选择器仿 WeGame
制作一个用户头像选择Canvas为父控件所实现，展示图片使用Image，Path当作上方的蒙版;
Canvas：主要用途方便移动Image，设置ClipToBounds="True"裁剪为一个正方形200x200做为主要展示区域;
Image：展示需要裁剪的图片；
Path：CombinedGeometry[1]绘制蒙版大小200x200效果如下；
当选择一个本地图片的时候判断宽与高谁更大，谁小就将它更改为200 ，另一边做等比缩放后给到DrawingVisual绘制一个新的BitmapFrame[2]给Image控件做展示；
当移动图片的时候右侧展示当前区域使用CroppedBitmap[3]进行裁剪并显示；
源码Github[4] Gitee[5]
核心代码
1）CropAvatar.xaml 代码如下；
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:controls="clr-namespace:WPFDevelopers.Controls">
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Basic/ControlBasic.xaml"/>
</ResourceDictionary.MergedDictionaries>
<Style TargetType="controls:CropAvatar" BasedOn="{StaticResource ControlBasicStyle}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type controls:CropAvatar}">
<Canvas x:Name="PART_Canvas" ClipToBounds="True">
<Image x:Name="PART_Image" Cursor="SizeAll" ></Image>
<Path x:Name="PART_Layout"
Fill="{DynamicResource BlackSolidColorBrush}"
Width="200" Height="200"
Opacity=".5">
<Path.Data>
<CombinedGeometry GeometryCombineMode="Xor">
<CombinedGeometry.Geometry1>
<RectangleGeometry Rect="0,0,200,200"/>
</CombinedGeometry.Geometry1>
<CombinedGeometry.Geometry2>
<EllipseGeometry Center="100,100" RadiusX="100" RadiusY="100"/>
</CombinedGeometry.Geometry2>
</CombinedGeometry>
</Path.Data>
</Path>
<Grid x:Name="PART_Grid" Width="200" Height="200">
<Button x:Name="PART_ReplaceButton" Style="{StaticResource PathButton}"
HorizontalAlignment="Right"
VerticalAlignment="Top"
Width="40" Height="40" ToolTip="更换图片"
Visibility="Collapsed">
<Button.Content>
<Path Data="{StaticResource PathReplace}"
Fill="{StaticResource PrimaryNormalSolidColorBrush}"
Height="15"
Width="15"
Stretch="Fill" />
</Button.Content>
</Button>
<Button x:Name="PART_AddButton" Style="{StaticResource PathButton}"
Width="40" Height="40" ToolTip="选择图片">
<Button.Content>
<Path Data="{StaticResource PathAdd}"
Fill="{StaticResource PrimaryNormalSolidColorBrush}"
Height="20"
Width="20"
Stretch="Fill"
RenderTransformOrigin="0.5,0.5" IsHitTestVisible="False">
<Path.RenderTransform>
<RotateTransform Angle="45"/>
</Path.RenderTransform>
</Path>
</Button.Content>
</Button>
</Grid>
</Canvas>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
2）CropAvatar.cs 代码如下;
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using WPFDevelopers.Helpers;
namespace WPFDevelopers.Controls
{
[TemplatePart(Name = CanvasTemplateName, Type = typeof(Canvas))]
[TemplatePart(Name = ImageTemplateName, Type = typeof(Image))]
[TemplatePart(Name = PathTemplateName, Type = typeof(Path))]
[TemplatePart(Name = GridTemplateName, Type = typeof(Grid))]
[TemplatePart(Name = ReplaceButtonTemplateName, Type = typeof(Button))]
[TemplatePart(Name = AddButtonTemplateName, Type = typeof(Button))]
public partial class CropAvatar : Control
{
private const string CanvasTemplateName = "PART_Canvas";
private const string ImageTemplateName = "PART_Image";
private const string PathTemplateName = "PART_Layout";
private const string GridTemplateName = "PART_Grid";
private const string ReplaceButtonTemplateName = "PART_ReplaceButton";
private const string AddButtonTemplateName = "PART_AddButton";
private Point point;
private const int _size = 200;
private bool isDown;
private bool isLeft;
private CroppedBitmap crop;
private Canvas canvas;
private Image image;
private Path path;
private Grid grid;
private Button replaceButton, addButton;
private int initialX, initialY, voffsetX, voffsetY;
private double vNewStartX, vNewStartY, _StartX, _StartY, centerX, centerY;
private BitmapFrame bitmapFrame;
public ImageSource OutImageSource
{
get { return (ImageSource)GetValue(OutImageSourceProperty); }
set { SetValue(OutImageSourceProperty, value); }
}
public static readonly DependencyProperty OutImageSourceProperty =
DependencyProperty.Register("OutImageSource", typeof(ImageSource), typeof(CropAvatar), new PropertyMetadata(null));
static CropAvatar()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(CropAvatar), new FrameworkPropertyMetadata(typeof(CropAvatar)));
}
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
canvas = GetTemplateChild(CanvasTemplateName) as Canvas;
canvas.Loaded += Canvas_Loaded;
grid = GetTemplateChild(GridTemplateName) as Grid;
image = GetTemplateChild(ImageTemplateName) as Image;
image.MouseDown += Image_MouseDown;
image.MouseMove += Image_MouseMove;
image.MouseUp += Image_MouseUp;
image.MouseLeave += Image_MouseLeave;
path = GetTemplateChild(PathTemplateName) as Path;
replaceButton = GetTemplateChild(ReplaceButtonTemplateName) as Button;
replaceButton.Click += ReplaceButton_Click;
addButton = GetTemplateChild(AddButtonTemplateName) as Button;
addButton.Click += AddButton_Click;
}
private void Canvas_Loaded(object sender, RoutedEventArgs e)
{
if (sender is Canvas canvas)
{
var width = canvas.ActualWidth;
var height = canvas.ActualHeight;
centerX = (width - path.Width) / 2.0d;
centerY = (height - path.Height) / 2.0d;
canvas.Clip = new RectangleGeometry(new Rect(centerX, centerY, 200, 200));
Canvas.SetLeft(path, centerX);
Canvas.SetTop(path, centerY);
Canvas.SetLeft(grid, centerX);
Canvas.SetTop(grid, centerY);
}
}
private void Image_MouseLeave(object sender, MouseEventArgs e)
{
isDown = false;
if (isLeft)
_StartX = Canvas.GetLeft(image);
else
_StartY = Canvas.GetTop(image);
}
private void Image_MouseUp(object sender, MouseButtonEventArgs e)
{
if (isDown)
{
var vPoint = e.GetPosition(this);
if (isLeft)
{
_StartX = Canvas.GetLeft(image);
initialX = voffsetX;
}
else
{
_StartY = Canvas.GetTop(image);
initialY = voffsetY;
}
}
}
private void Image_MouseMove(object sender, MouseEventArgs e)
{
if (e.LeftButton == MouseButtonState.Pressed && isDown)
{
var vPoint = e.GetPosition(this);
if (isLeft)
{
var voffset = vPoint.X - point.X;
vNewStartX = _StartX + voffset;
var xPath = Canvas.GetLeft(path);
if (vNewStartX <= xPath && vNewStartX >= -(bitmapFrame.Width - 200 - xPath))
{
Canvas.SetLeft(image, vNewStartX);
voffsetX = initialX - (int)voffset;
voffsetX = voffsetX < 0 ? 0 : voffsetX;
crop = new CroppedBitmap(bitmapFrame, new Int32Rect(voffsetX, 0, _size, _size));
}
}
else
{
var voffset = vPoint.Y - point.Y;
vNewStartY = _StartY + voffset;
var yPath = Canvas.GetTop(path);
if (vNewStartY <= yPath && vNewStartY >= -(bitmapFrame.Height - 200 - yPath))
{
Canvas.SetTop(image, vNewStartY);
voffsetY = initialY - (int)voffset;
voffsetY = voffsetY < 0 ? 0 : voffsetY;
crop = new CroppedBitmap(bitmapFrame, new Int32Rect(0, voffsetY, _size, _size));
}
}
OutImageSource = crop;
}
}
private void Image_MouseDown(object sender, MouseButtonEventArgs e)
{
isDown = true;
point = e.GetPosition(this);
}
private void ReplaceButton_Click(object sender, RoutedEventArgs e)
{
InitialImage();
}
private void AddButton_Click(object sender, RoutedEventArgs e)
{
InitialImage();
}
void InitialImage()
{
vNewStartX = 0;
vNewStartY = 0;
var uri = ControlsHelper.ImageUri();
if (uri == null) return;
var bitmap = new BitmapImage(uri);
if (bitmap.Height > bitmap.Width)
{
double scale = (double)bitmap.Width / (double)path.Width;
image.Width = _size;
image.Height = (double)bitmap.Height / scale;
isLeft = false;
}
else if (bitmap.Width > bitmap.Height)
{
double scale = (double)bitmap.Height / (double)path.Height;
image.Width = (double)bitmap.Width / scale;
image.Height = _size;
isLeft = true;
}
bitmapFrame = ControlsHelper.CreateResizedImage(bitmap, (int)image.Width, (int)image.Height, 0);
image.Source = bitmapFrame;
if (image.Source != null)
{
replaceButton.Visibility = Visibility.Visible;
addButton.Visibility = Visibility.Collapsed;
}
Canvas.SetLeft(grid, centerX);
Canvas.SetTop(grid, centerY);
_StartX = (canvas.ActualWidth - image.Width) / 2.0d;
_StartY = (canvas.ActualHeight - image.Height) / 2.0d;
Canvas.SetLeft(image, _StartX);
Canvas.SetTop(image, _StartY);
if (isLeft)
{
initialX = (int)(image.Width - 200) / 2;
initialY = 0;
crop = new CroppedBitmap(bitmapFrame, new Int32Rect(initialX, 0, _size, _size));
}
else
{
initialY = (int)(image.Height - 200) / 2;
initialX = 0;
crop = new CroppedBitmap(bitmapFrame, new Int32Rect(0, initialY, _size, _size));
}
OutImageSource = crop;
}
}
}3）CropAvatarWindow.xaml使用如下；
<ws:Window x:Class="WPFDevelopers.Samples.ExampleViews.CropAvatarWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:wpfdev="https://github.com/WPFDevelopersOrg/WPFDevelopers"
xmlns:ws="https://github.com/WPFDevelopersOrg.WPFDevelopers.Minimal"
mc:Ignorable="d" WindowStyle="ToolWindow" ResizeMode="NoResize"
WindowStartupLocation="CenterScreen"
Title="WPF 开发者-头像选择器" Height="450" Width="800">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<wpfdev:CropAvatar x:Name="MyCropAvatar"/>
<Image Grid.Column="1" Name="CropAvatarImage" Source="{Binding ElementName=MyCropAvatar,Path=OutImageSource}"
Stretch="Fill" Width="200" Height="200">
<Image.Clip>
<EllipseGeometry Center="100,100" RadiusX="100" RadiusY="100"/>
</Image.Clip>
</Image>
<UniformGrid Grid.Row="1" Grid.ColumnSpan="2"
HorizontalAlignment="Center"
VerticalAlignment="Center">
<Button Content="保存" Click="btnSave_Click" Style="{StaticResource PrimaryButton}" Margin="4,0"/>
<Button Content="关闭" Click="btnClose_Click" Margin="4,0"/>
</UniformGrid>
</Grid>
</ws:Window>4） CropAvatarWindow.xaml.cs 代码如下；
using System.Windows;
namespace WPFDevelopers.Samples.ExampleViews
{
/// <summary>
/// CropAvatarWindow.xaml 的交互逻辑
/// </summary>
public partial class CropAvatarWindow
{
public CropAvatarWindow()
{
InitializeComponent();
}
private void btnSave_Click(object sender, RoutedEventArgs e)
{
DialogResult = true;
}
private void btnClose_Click(object sender, RoutedEventArgs e)
{
DialogResult = false;
}
}
}5） CropAvatarExample.xaml 使用如下；
<UserControl x:Class="WPFDevelopers.Samples.ExampleViews.CropAvatarExample"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:wpfdev="https://github.com/WPFDevelopersOrg/WPFDevelopers"
xmlns:local="clr-namespace:WPFDevelopers.Samples.ExampleViews"
mc:Ignorable="d"
d:DesignHeight="450" d:DesignWidth="800">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Button Content="图像选择器" VerticalAlignment="Center" HorizontalAlignment="Center" Click="Button_Click"/>
<Image Grid.Column="1" Name="MyImage"
Stretch="Fill" Width="200" Height="200">
<Image.Clip>
<EllipseGeometry Center="100,100" RadiusX="100" RadiusY="100"/>
</Image.Clip>
</Image>
</Grid>
</UserControl>
6） CropAvatarExample.xaml.cs 代码如下；
using System.Windows.Controls;
namespace WPFDevelopers.Samples.ExampleViews
{
/// <summary>
/// CropAvatarExample.xaml 的交互逻辑
/// </summary>
public partial class CropAvatarExample : UserControl
{
public CropAvatarExample()
{
InitializeComponent();
}
private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
{
var cropAvatarWindow = new CropAvatarWindow();
if (cropAvatarWindow.ShowDialog() == true)
{
MyImage.Source = cropAvatarWindow.CropAvatarImage.Source;
}
}
}
}参考资料
[1]CombinedGeometry
[2]BitmapFrame
[3]CroppedBitmap
[4]Github
[5]Gitee
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