重新想象 Windows 8 Store Apps (29)
[源码下载]重新想象 Windows 8 Store Apps (29) - 图片处理
作者：webabcd
介绍
重新想象 Windows 8 Store Apps 之 图片处理
[*]显示图片
[*]图片的 9 切片
[*]WriteableBitmap
[*]获取和修改图片属性
[*]对图片文件做“缩放/旋转/编码”操作，并保存操作后的结果
示例
1、演示最基础的图片显示
Image/Display.xaml
Image/Display.xaml.cs
/*
* 演示最基础的图片显示
*
* 注：
* 1、引用 package 中的图片用：ms-appx:///
* 2、引用 ApplicationData 中的图片：
* a) LocalFolder 对应 ms-appdata:///local/
* b) RoamingFolder 对应 ms-appdata:///roaming/
* c) TemporaryFolder 对应 ms-appdata:///temp/
*/
using System;
using Windows.Storage.Streams;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;
using Windows.UI.Xaml.Navigation;
namespace XamlDemo.Image
{
public sealed partial class Display : Page
{
public Display()
{
this.InitializeComponent();
}
protected async override void OnNavigatedTo(NavigationEventArgs e)
{
// code-behind 指定图片源
img.Source = new BitmapImage(new Uri("ms-appx:///Assets/Logo.png", UriKind.Absolute));
// code-behind 指定图片源
RandomAccessStreamReference imageStreamRef = RandomAccessStreamReference.CreateFromUri(new Uri("ms-appx:///Assets/Logo.png", UriKind.Absolute));
IRandomAccessStream imageStream = await imageStreamRef.OpenReadAsync();
BitmapImage bitmapImage = new BitmapImage();
bitmapImage.SetSource(imageStream);
img2.Source = bitmapImage;
}
}
}
2、演示图片的 NineGrid
Image/NineGrid.xaml
3、演示 WriteableBitmap 的应用
Image/WriteableBitmapDemo.xaml
Image/WriteableBitmapDemo.xaml.cs
/*
* 演示 WriteableBitmap 的应用
*
* 注：WriteableBitmap 使用的是 BGRA 格式
*/
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;
using System;
using System.IO;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Graphics.Imaging;
using Windows.Storage;
using Windows.Storage.Streams;
namespace XamlDemo.Image
{
public sealed partial class WriteableBitmapDemo : Page
{
public WriteableBitmapDemo()
{
this.InitializeComponent();
}
// 加载一个图片
private async void btnLoadImage_Click_1(object sender, RoutedEventArgs e)
{
// 实例化一个 300*300 的 WriteableBitmap，并将其作为 Image 控件的图片源
WriteableBitmap writeableBitmap = new WriteableBitmap(300, 300);
img.Source = writeableBitmap;
StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///Assets/Logo.png"));
using (IRandomAccessStream fileStream = await file.OpenAsync(FileAccessMode.Read))
{
// 设置 WriteableBitmap 对象的图片流
await writeableBitmap.SetSourceAsync(fileStream);
}
}
// 加载一个图片并修改其中的像素的颜色值
private async void btnChangePixel_Click_1(object sender, RoutedEventArgs e)
{
// 实例化一个 300*300 的 WriteableBitmap，并将其作为 Image 控件的图片源
WriteableBitmap writeableBitmap = new WriteableBitmap(300, 300);
img.Source = writeableBitmap;
StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///Assets/Logo.png"));
using (IRandomAccessStream fileStream = await file.OpenAsync(FileAccessMode.Read))
{
// 将指定的图片转换成 BitmapDecoder 对象
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
// 通过 BitmapTransform 缩放图片的尺寸
BitmapTransform transform = new BitmapTransform()
{
ScaledWidth = Convert.ToUInt32(writeableBitmap.PixelWidth),
ScaledHeight = Convert.ToUInt32(writeableBitmap.PixelHeight)
};
// 获取图片的 PixelDataProvider 对象
PixelDataProvider pixelData = await decoder.GetPixelDataAsync(
BitmapPixelFormat.Bgra8,
BitmapAlphaMode.Straight,
transform,
ExifOrientationMode.IgnoreExifOrientation,
ColorManagementMode.DoNotColorManage);
// 获取图片的像素数据，由于之前指定的格式是 BitmapPixelFormat.Bgra8，所以每一个像素由 4 个字节组成，分别是 bgra
byte[] sourcePixels = pixelData.DetachPixelData();
for (int i = 0; i < sourcePixels.Length; i++)
{
sourcePixels -= 10;
}
// 将修改后的像素数据写入 WriteableBitmap 对象的像素缓冲区（WriteableBitmap 使用的是 BGRA 格式）
using (Stream stream = writeableBitmap.PixelBuffer.AsStream()) // IBuffer.AsStream() 为来自 System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeBufferExtensions 中的扩展方法
{
await stream.WriteAsync(sourcePixels, 0, sourcePixels.Length);
}
}
// 用像素缓冲区的数据绘制图片
writeableBitmap.Invalidate();
}
// 创建一个图片，设置其每个像素的颜色值
private async void btnCreatePixel_Click_1(object sender, RoutedEventArgs e)
{
// 实例化一个 300*300 的 WriteableBitmap，并将其作为 Image 控件的图片源
WriteableBitmap writeableBitmap = new WriteableBitmap(300, 300);
img.Source = writeableBitmap;
Random random = new Random();
// 设置需要绘制的图片的像素数据（每一个像素由 4 个字节组成，分别是 bgra）
byte[] result = new byte;
for (int i = 0; i < result.Length; )
{
result = (byte)random.Next(0, 256); // Green
result = (byte)random.Next(0, 256); // Blue
result = (byte)random.Next(0, 256); // Red
result = 255; // Alpha
}
// 将像素数据写入 WriteableBitmap 对象的像素缓冲区
using (Stream stream = writeableBitmap.PixelBuffer.AsStream())
{
await stream.WriteAsync(result, 0, result.Length);
}
// 用像素缓冲区的数据绘制图片
writeableBitmap.Invalidate();
}
}
}
4、演示如何获取、修改图片属性
Image/ImageProperty.xaml.cs
/*
* 演示如何获取、修改图片属性
*/
using System;
using System.Threading.Tasks;
using Windows.Storage;
using Windows.Storage.FileProperties;
using Windows.Storage.Pickers;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using XamlDemo.Common;
namespace XamlDemo.Image
{
public sealed partial class ImageProperty : Page
{
public ImageProperty()
{
this.InitializeComponent();
}
protected async override void OnNavigatedTo(NavigationEventArgs e)
{
if (Helper.EnsureUnsnapped())
{
// 选择一个图片文件
FileOpenPicker picker = new FileOpenPicker();
picker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.PicturesLibrary;
picker.FileTypeFilter.Add(".jpg");
picker.FileTypeFilter.Add(".png");
StorageFile file = await picker.PickSingleFileAsync();
if (file != null)
{
ImageProperties imageProperties = await GetImageProperty(file);
UpdateImageProperty(imageProperties);
}
}
}
// 获取图片属性
private async Task GetImageProperty(StorageFile file)
{
// 获取图片文件的图片属性信息
ImageProperties imageProperties = await file.Properties.GetImagePropertiesAsync();
// 显示图片文件的图片属性（以下试举几例，不全）
lblMsg.Text = "title: " + imageProperties.Title;
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "keywords: " + string.Join(",", imageProperties.Keywords);
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "width: " + imageProperties.Width;
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "height: " + imageProperties.Height;
lblMsg.Text += Environment.NewLine;
return imageProperties;
}
// 更新图片属性
private async void UpdateImageProperty(ImageProperties imageProperties)
{
Random random = new Random();
// 设置图片文件的图片属性（以下试举几例，不全）
imageProperties.Title = random.Next(0, 1000).ToString();
imageProperties.Keywords.Clear();
imageProperties.Keywords.Add(random.Next(0, 1000).ToString());
imageProperties.Keywords.Add(random.Next(0, 1000).ToString());
try
{
// 保存图片文件的图片属性信息
await imageProperties.SavePropertiesAsync();
lblMsg.Text += "title 和 keywords 已被修改，重新进来可看效果";
}
catch (Exception ex)
{
lblMsg.Text = ex.ToString();
}
}
}
}
5、演示如何对图片文件做“缩放/旋转/编码”操作，并保存操作后的结果
Image/ImageTransform.xaml
Image/ImageTransform.xaml.cs
/*
* 演示如何对图片文件做“缩放/旋转/编码”操作，并保存操作后的结果
*/
using System;
using Windows.Graphics.Imaging;
using Windows.Storage;
using Windows.Storage.Pickers;
using Windows.Storage.Streams;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;
using Windows.UI.Xaml.Navigation;
using XamlDemo.Common;
namespace XamlDemo.Image
{
public sealed partial class ImageTransform : Page
{
public ImageTransform()
{
this.InitializeComponent();
}
protected async override void OnNavigatedTo(NavigationEventArgs e)
{
if (Helper.EnsureUnsnapped())
{
// 选择一个 .jpg 图片文件
FileOpenPicker picker = new FileOpenPicker();
picker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.PicturesLibrary;
picker.FileTypeFilter.Add(".jpg");
StorageFile fileRead = await picker.PickSingleFileAsync();
if (fileRead != null)
{
// 显示用户选中的图片文件
BitmapImage src = new BitmapImage();
src.SetSource(await fileRead.OpenAsync(FileAccessMode.Read));
imgOriginal.Source = src;
// 定义一个转换后的图片文件
StorageFile fileWrite = await ApplicationData.Current.TemporaryFolder.CreateFileAsync(@"webabcdTest\imageTransformDemo.png", CreationCollisionOption.ReplaceExisting);
using (IRandomAccessStream inputStream = await fileRead.OpenAsync(FileAccessMode.Read), outputStream = await fileWrite.OpenAsync(FileAccessMode.ReadWrite))
{
// 将用户选择的图片文件转换为一个 BitmapDecoder 对象
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(inputStream);
// 通过 BitmapTransform 来配置图片的宽度、高度和顺时针旋转角度
BitmapTransform transform = new BitmapTransform();
transform.ScaledWidth = 100;
transform.ScaledHeight = 100;
transform.Rotation = BitmapRotation.Clockwise180Degrees;
// 获取图片的 PixelDataProvider 对象
PixelDataProvider pixelProvider = await decoder.GetPixelDataAsync(
decoder.BitmapPixelFormat,
decoder.BitmapAlphaMode,
transform,
ExifOrientationMode.RespectExifOrientation,
ColorManagementMode.ColorManageToSRgb
);
// 获取经过了 BitmapTransform 转换后的图片的像素数据
byte[] pixels = pixelProvider.DetachPixelData();
// 创建一个 BitmapEncoder 对象，可以指定图片的编码格式（PngEncoderId, JpegEncoderId, JpegXREncoderId, GifEncoderId, TiffEncoderId）
BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, outputStream);
// 转码像素数据到指定的图片编码格式（本例会转吗为 png 格式），并将转码后的数据写入 stream 缓冲区
encoder.SetPixelData(
decoder.BitmapPixelFormat,
decoder.BitmapAlphaMode,
100,
100,
decoder.DpiX,
decoder.DpiY,
pixels
);
// 提交 stream 缓冲区中的所有内容
await encoder.FlushAsync();
}
// 显示经过“缩放/旋转/编码”操作后的图片文件
imgTransformed.Source = new BitmapImage(new Uri("ms-appdata:///temp/webabcdTest/imageTransformDemo.png", UriKind.Absolute));
}
}
}
}
}
OK
[源码下载]
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