我需要图像比例，翻译和裁剪的功能，就像照片选择器任务在Windows Phone 8.1中所做的那样。我无法使用照片选择器任务，因为我不会从媒体照片库中选择照片或捕获图像。为了我的目的，将从服务器保存的图片列表中选择图像。我已为此编写了一些代码，但它没有按照我的意愿工作。我正在研究它4周但很难找到完美的解决方案。这是我的代码。
这是xaml代码
<phone:PhoneApplicationPage
x:Class="TransformationLearning.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneForegroundBrush}"
SupportedOrientations="Portrait" Orientation="Portrait"
shell:SystemTray.IsVisible="True">
<!--LayoutRoot is the root grid where all page content is placed-->
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
<TextBlock Text="Transformation" Style="{StaticResource PhoneTextNormalStyle}" Margin="12,0"/>
<TextBlock Text="page name" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
</StackPanel>
<Grid Grid.Row="1" Background="Yellow">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid Name="grid"
Grid.Row="0"
Height="400"
Width="400"
>
<Image x:Name="myImage" Source="/Assets/Lion.jpg"
Stretch="UniformToFill"
ManipulationCompleted="CompleteManipulation"
ManipulationDelta="DeltaManipulation"
Loaded="ImageLoaded"
Grid.Row="1"
>
<Image.RenderTransform>
<CompositeTransform x:Name="myComposite"
/>
</Image.RenderTransform>
</Image>
<Rectangle Width="200"
Height="200"
Name="myRectangle"
Margin="100 100"
Stroke="White"
StrokeThickness="3" Grid.Row="1">
</Rectangle>
</Grid>
<Image Name="myCropPicture" Grid.Row="1"/>
</Grid>
</Grid>
</phone:PhoneApplicationPage>
这是背后的代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using TransformationLearning.Resources;
using Microsoft.Xna.Framework;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.IO;
using Lumia.Imaging;
using Lumia.Imaging.Transforms;
using System.Threading.Tasks;
using Windows.Storage.Streams;
using Windows.Storage;
using System.Windows.Controls.Primitives;
using System.Runtime.InteropServices.WindowsRuntime;
namespace TransformationLearning
{
public partial class MainPage : PhoneApplicationPage
{
WriteableBitmap WB_CapturedImage;//for original image
WriteableBitmap WB_CroppedImage;//for cropped image
double width, height;
WriteableBitmap wb;
CompositeTransform transform;
GeneralTransform gt, gt1;
System.Windows.Point absolutePosition, absolutePosition1;
public MainPage()
{
InitializeComponent();
transform = new CompositeTransform();
}
private void ImageLoaded(object sender, RoutedEventArgs e)
{
wb = new WriteableBitmap(myImage, null);
myComposite.CenterX = 150;
myComposite.CenterY = 150;
}
private double BoundaryCheck(double value)
{
if (value < 1.0)
return 1.0;
else if (value > 2.0)
return 2.0;
else
return value;
}
private void DeltaManipulation(object sender, System.Windows.Input.ManipulationDeltaEventArgs e)
{
transform = myComposite;
if (e.DeltaManipulation.Scale.X == 0.0 || e.DeltaManipulation.Scale.Y == 0.0)
{
myComposite.ScaleX *= 1.0;
myComposite.ScaleY *= 1.0;
}
else if (e.DeltaManipulation.Scale.X > 0.0)
{
double value = BoundaryCheck(myComposite.ScaleX*e.DeltaManipulation.Scale.X);
myComposite.ScaleX = myComposite.ScaleY = value;
gt = myImage.TransformToVisual(grid);
absolutePosition = gt.Transform(new System.Windows.Point(0, 0));
gt1 = myRectangle.TransformToVisual(grid);
absolutePosition1 = gt1.Transform(new System.Windows.Point(0, 0));
if ((absolutePosition1.X <= absolutePosition.X)
|| (absolutePosition1.Y <= absolutePosition.Y)
|| (absolutePosition1.X + myRectangle.Width >= absolutePosition.X + wb.PixelWidth)
|| (absolutePosition1.Y + myRectangle.Height >= absolutePosition.Y + wb.PixelHeight))
{
myComposite = transform;
}
}
gt = myImage.TransformToVisual(grid);
absolutePosition = gt.Transform(new System.Windows.Point(0, 0));
gt1 = myRectangle.TransformToVisual(grid);
absolutePosition1 = gt1.Transform(new System.Windows.Point(0, 0));
if (e.DeltaManipulation.Translation.Y > 0.0 && (absolutePosition1.Y >= (absolutePosition.Y + e.DeltaManipulation.Translation.Y)))
{
myComposite.TranslateY += (e.DeltaManipulation.Translation.Y-2);
}
if (e.DeltaManipulation.Translation.X > 0.0 && (absolutePosition1.X >= (absolutePosition.X + e.DeltaManipulation.Translation.X)))
{
myComposite.TranslateX += (e.DeltaManipulation.Translation.X - 2);
}
if (e.DeltaManipulation.Translation.Y < 0.0 && ((absolutePosition1.Y + myRectangle.Height) <= (absolutePosition.Y + e.DeltaManipulation.Translation.Y + wb.PixelHeight)))
{
myComposite.TranslateY += (e.DeltaManipulation.Translation.Y + 2);
}
if (e.DeltaManipulation.Translation.X < 0.0 && ((absolutePosition1.X + myRectangle.Width) <= (absolutePosition.X + e.DeltaManipulation.Translation.X + wb.PixelWidth)))
{
myComposite.TranslateX += (e.DeltaManipulation.Translation.X + 2);
}
wb = new WriteableBitmap(myImage, myComposite);
gt = myImage.TransformToVisual(grid);
absolutePosition = gt.Transform(new System.Windows.Point(0, 0));
}
private void CompleteManipulation(object sender, System.Windows.Input.ManipulationCompletedEventArgs e)
{
App.RootFrame.RenderTransform = new CompositeTransform();
grid.UpdateLayout();
CropImage();
App.RootFrame.RenderTransform = new CompositeTransform();
grid.UpdateLayout();
}
private async void CropImage()
{
var ms = new MemoryStream();
wb.SaveJpeg(ms, wb.PixelWidth, wb.PixelHeight, 0, 100);
ms.Position = 0;
gt1 = myRectangle.TransformToVisual(myImage);
absolutePosition1 = gt1.Transform(new System.Windows.Point(0, 0));
using (var source = new StreamImageSource(ms))
{
using (var filterEffect = new FilterEffect(source))
{
var filter = new CropFilter(new Windows.Foundation.Rect(absolutePosition1.X, absolutePosition1.Y, myRectangle.Width, myRectangle.Height));
filterEffect.Filters = new IFilter[] { filter };
var target = new WriteableBitmap((int)(myRectangle.Width), (int)(myRectangle.Height));
using (var renderer = new WriteableBitmapRenderer(filterEffect, target))
{
try
{
await renderer.RenderAsync();
}
catch (Exception t)
{
System.Diagnostics.Debug.WriteLine(t.InnerException);
System.Diagnostics.Debug.WriteLine(t.Message);
}
}
myCropPicture.Source = target;
}
}
}
}
}
这里我使用了Lumia Imaging SDK裁剪滤镜来裁剪图像。 ＆＃34; MYIMAGE＆＃34;是源图像和＆＃34; myCropPicture＆＃34;用于显示裁剪的图像。为了转换，我使用了复合变换。当我缩放源图像时，此代码无法相应地裁剪该图像。我非常需要帮助。