Metro style app
一.图片Scale ,Crop操作
public
class
PhotoEdit
{
public
async
static
Task<WriteableBitmap> ScaleAndCorpPhoto(IStorageFile file)
{
if
(file ==
null
)
return
null
;
// create a stream from the file and decode the image
var
fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read);
BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
BitmapTransform transform =
new
BitmapTransform();
BitmapBounds bounds =
new
BitmapBounds();
transform.ScaledWidth = 500;
transform.ScaledHeight = 500;
const
int
croppedHeight = 400;
const
int
croppedWidth = 400;
bounds.Height = croppedHeight;
bounds.Width = croppedWidth;
bounds.X = 0;
bounds.Y = 0;
transform.Bounds = bounds;
// Get the pixels in Bgra8 to match what the WriteableBitmap will expect
PixelDataProvider pixelData = await decoder.GetPixelDataAsync(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Straight, transform, ExifOrientationMode.RespectExifOrientation, ColorManagementMode.ColorManageToSRgb);
byte
[] pixels = pixelData.DetachPixelData();
// And stream them into a WriteableBitmap
WriteableBitmap cropBmp =
new
WriteableBitmap(croppedHeight, croppedWidth);
Stream pixStream = cropBmp.PixelBuffer.AsStream();
pixStream.Write(pixels, 0, pixels.Length);
return
cropBmp;
}
}
|
调用方法
private
async System.Threading.Tasks.Task ScaleAndCorpPhoto()
{
FileOpenPicker fileOpenPicker =
new
FileOpenPicker();
fileOpenPicker.CommitButtonText =
"打开"
;
fileOpenPicker.FileTypeFilter.Insert(0,
".jpg"
);
StorageFile file = await fileOpenPicker.PickSingleFileAsync();
if
(file ==
null
)
return
;
image.Source = await PhotoEdit.ScaleAndCorpPhoto(file);
}
|
二、图片的打开与保存
1.图片的打开. 选择要显示的图片,最后将图片显示在Image控件中.
private
static
BitmapImage srcImage =
new
BitmapImage();
private
static
WriteableBitmap wbsrcImage;
public
async
static
void
OpenImage(Image ImageOne)
{
FileOpenPicker imagePicker =
new
FileOpenPicker
{
ViewMode = PickerViewMode.Thumbnail,
SuggestedStartLocation = PickerLocationId.PicturesLibrary,
FileTypeFilter = {
".jpg"
,
".jpeg"
,
".png"
,
".bmp"
}
};
Guid decoderId;
StorageFile imageFile = await imagePicker.PickSingleFileAsync();
if
(imageFile !=
null
)
{
srcImage =
new
BitmapImage();
using
(IRandomAccessStream stream = await imageFile.OpenAsync(FileAccessMode.Read))
{
srcImage.SetSource(stream);
switch
(imageFile.FileType.ToLower())
{
case
".jpg"
:
case
".jpeg"
:
decoderId = Windows.Graphics.Imaging.BitmapDecoder.JpegDecoderId;
break
;
case
".bmp"
:
decoderId = Windows.Graphics.Imaging.BitmapDecoder.BmpDecoderId;
break
;
case
".png"
:
decoderId = Windows.Graphics.Imaging.BitmapDecoder.PngDecoderId;
break
;
default
:
return
;
}
Windows.Graphics.Imaging.BitmapDecoder decoder = await Windows.Graphics.Imaging.BitmapDecoder.CreateAsync(decoderId, stream);
int
width = (
int
)decoder.PixelWidth;
int
height = (
int
)decoder.PixelHeight;
Windows.Graphics.Imaging.PixelDataProvider dataprovider = await decoder.GetPixelDataAsync();
byte
[] pixels = dataprovider.DetachPixelData();
wbsrcImage =
new
WriteableBitmap(width, height);
Stream pixelStream = wbsrcImage.PixelBuffer.AsStream();
//rgba in original
//to display ,convert tobgra
for
(
int
i = 0; i < pixels.Length; i += 4)
{
byte
temp = pixels[i];
pixels[i] = pixels[i + 2];
pixels[i + 2] = temp;
}
pixelStream.Write(pixels, 0, pixels.Length);
pixelStream.Dispose();
stream.Dispose();
}
ImageOne.Source = wbsrcImage;
ImageOne.Width = wbsrcImage.PixelWidth;
ImageOne.Height = wbsrcImage.PixelHeight;
}
}
|
2.图片的保存. 将获得的WriteableBitmap保存起来. 比如你可以将Scale和Crop的图片保存起来.
public
async
static
Task SaveImage(WriteableBitmap src)
{
FileSavePicker save =
new
FileSavePicker();
save.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
save.DefaultFileExtension =
".jpg"
;
save.SuggestedFileName =
"newimage"
;
save.FileTypeChoices.Add(
".bmp"
,
new
List<
string
>() {
".bmp"
});
save.FileTypeChoices.Add(
".png"
,
new
List<
string
>() {
".png"
});
save.FileTypeChoices.Add(
".jpg"
,
new
List<
string
>() {
".jpg"
,
".jpeg"
});
StorageFile savedItem = await save.PickSaveFileAsync();
try
{
Guid encoderId;
switch
(savedItem.FileType.ToLower())
{
case
".jpg"
:
encoderId = BitmapEncoder.JpegEncoderId;
break
;
case
".bmp"
:
encoderId = BitmapEncoder.BmpEncoderId;
break
;
case
".png"
:
default
:
encoderId = BitmapEncoder.PngEncoderId;
break
;
}
IRandomAccessStream fileStream = await savedItem.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite);
BitmapEncoder encoder = await BitmapEncoder.CreateAsync(encoderId, fileStream);
Stream pixelStream = src.PixelBuffer.AsStream();
byte
[] pixels =
new
byte
[pixelStream.Length];
pixelStream.Read(pixels, 0, pixels.Length);
//pixal format shouldconvert to rgba8
for
(
int
i = 0; i < pixels.Length; i += 4)
{
byte
temp = pixels[i];
pixels[i] = pixels[i + 2];
pixels[i + 2] = temp;
}
encoder.SetPixelData(
BitmapPixelFormat.Rgba8,
BitmapAlphaMode.Straight,
(
uint
)src.PixelWidth,
(
uint
)src.PixelHeight,
96,
// Horizontal DPI
96,
// Vertical DPI
pixels
);
await encoder.FlushAsync();
}
catch
(Exception e)
{
throw
e;
}
}
|
本文转自Work Hard Work Smart博客园博客，原文链接：http://www.cnblogs.com/linlf03/archive/2012/11/28/2792726.html，如需转载请自行联系原作者
