问题
I have a WPF InkCanvas control I'm using to capture a signature in my application. The control looks like this - it's 700x300
However, when I save it as a JPG, the resulting image looks like this, also 700x300
The code I'm using to save
sigPath = System.IO.Path.GetTempFileName();
MemoryStream ms = new MemoryStream();
FileStream fs = new FileStream(sigPath, FileMode.Create);
RenderTargetBitmap rtb = new RenderTargetBitmap((int)inkSig.Width, (int)inkSig.Height, 96d, 96d, PixelFormats.Default);
rtb.Render(inkSig);
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(rtb));
encoder.Save(fs);
fs.Close();
This is the XAML I'm using:
<Window x:Class="Consent.Client.SigPanel"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Background="Transparent" Topmost="True" AllowsTransparency="True"
Title="SigPanel" Left="0" Top="0" Height="1024" Width="768" WindowStyle ="None" ShowInTaskbar="False" ResizeMode="NoResize" WindowStartupLocation="CenterScreen" >
<Border BorderThickness="1" BorderBrush="Black" Background='#FFFFFFFF' x:Name='DocumentRoot' Width='750' Height='400' CornerRadius='10'>
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
<TextBlock Name="txtLabel" FontSize="24" HorizontalAlignment="Center" >Label</TextBlock>
<InkCanvas Opacity="1" Background="Beige" Name="inkSig" Width="700" Height="300" />
<StackPanel HorizontalAlignment="Center" Orientation="Horizontal">
<Button FontSize="24" Margin="10" Width="150" Name="btnSave" Click="btnSave_Click">Save</Button>
<Button FontSize="24" Margin="10" Width="150" Name="btnCancel" Click="btnCancel_Click">Cancel</Button>
<Button FontSize="24" Margin="10" Width="150" Name="btnClear" Click="btnClear_Click">Clear</Button>
</StackPanel>
</StackPanel>
</Border>
In the past this worked perfectly. I can't figure out what changed that is causing the image to shift when it is saved.
回答1:
Aha! The problem is the TextBlock txtLabel that is directly above the InkCanvas. When you remove that the black line disappears.
As for why that is happening, I'm not entirely sure yet.
回答2:
I had same problem i did this way.. It worked here..
private void Button_Click(object sender, RoutedEventArgs e)
{
double width = inkSig.ActualWidth;
double height = inkSig.ActualHeight;
RenderTargetBitmap bmpCopied = new RenderTargetBitmap((int)Math.Round(width), (int)Math.Round(height), 96, 96, PixelFormats.Default);
DrawingVisual dv = new DrawingVisual();
using (DrawingContext dc = dv.RenderOpen())
{
VisualBrush vb = new VisualBrush(inkSig);
dc.DrawRectangle(vb, null, new Rect(new System.Windows.Point(), new System.Windows.Size(width, height)));
}
bmpCopied.Render(dv);
System.Drawing.Bitmap bitmap;
using (MemoryStream outStream = new MemoryStream())
{
// from System.Media.BitmapImage to System.Drawing.Bitmap
BitmapEncoder enc = new BmpBitmapEncoder();
enc.Frames.Add(BitmapFrame.Create(bmpCopied));
enc.Save(outStream);
bitmap = new System.Drawing.Bitmap(outStream);
}
EncoderParameter qualityParam =
new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 85L);
// Jpeg image codec
ImageCodecInfo jpegCodec = getEncoderInfo("image/jpeg");
if (jpegCodec == null)
return;
EncoderParameters encoderParams = new EncoderParameters(1);
encoderParams.Param[0] = qualityParam;
Bitmap btm = new Bitmap(bitmap);
bitmap.Dispose();
btm.Save("C:\\Users\\Pd\\Desktop\\dfe12.jpg", jpegCodec, encoderParams);
btm.Dispose();
}
private ImageCodecInfo getEncoderInfo(string mimeType)
{
// Get image codecs for all image formats
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
// Find the correct image codec
for (int i = 0; i < codecs.Length; i++)
if (codecs[i].MimeType == mimeType)
return codecs[i];
return null;
}
回答3:
My class save image
using System;
using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;
public void ExportToJpeg(String path, InkCanvas surface)
{
double
x1 = surface.Margin.Left,
x2 = surface.Margin.Top,
x3 = surface.Margin.Right,
x4 = surface.Margin.Bottom;
if (path == null) return;
surface.Margin = new Thickness(0, 0, 0, 0);
Size size = new Size(surface.Width, surface.Height);
surface.Measure(size);
surface.Arrange(new Rect(size));
RenderTargetBitmap renderBitmap =
new RenderTargetBitmap(
(int)size.Width,
(int)size.Height,
96,
96,
PixelFormats.Default);
renderBitmap.Render(surface);
using (FileStream fs = File.Open(path, FileMode.Create))
{
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(renderBitmap));
encoder.Save(fs);
}
surface.Margin = new Thickness(x1, x2, x3, x4);
}
回答4:
and surface.Margin = new Thickness(55,40,96,5); http://img519.imageshack.us/img519/7499/mynewimage.png
回答5:
Jason, I solved this problem.
Sorry my English. I am Russian.
You need set property inkCanvas.Margin at 0,0,0,0
with:
surface.Margin = new Thickness(0, 0, 0, 0);
after saving set margin at your position.
example: http://img189.imageshack.us/img189/7499/mynewimage.png
回答6:
var size = new Size(inkCanvas.ActualWidth, inkCanvas.ActualHeight);
inkCanvas.Margin = new Thickness(0, 0, 0, 0);
inkCanvas.Measure(size);
inkCanvas.Arrange(new Rect(size));
var encoder = new PngBitmapEncoder();
var bitmapTarget = new RenderTargetBitmap((int)size.Width, (int)size.Height, 96, 96, PixelFormats.Default);
bitmapTarget.Render(inkCanvas);
encoder.Frames.Add(BitmapFrame.Create(bitmapTarget));
encoder.Save(ms);
回答7:
I've been looking all over the net for an answer to this problem and tried most opinions without any joy. Then I tried this and it worked!
<Canvas x:Name="editCanvas" Background="Transparent" ClipToBounds="True">
<InkCanvas EditingMode="Select" x:Name="inkCanvas" Background="Transparent" Height="562" Width="866">
</InkCanvas>
</Canvas>
来源：https://stackoverflow.com/questions/1234447/saving-wpf-inkcanvas-to-a-jpg-image-is-getting-cropped