I would like to zoom an image in WPF and that the image visual render be inside a constrained sized item control.
For example:
<Canvas x:Name="m_canvas" MaxWidth="300" MaxHeight="300" >
<Image Source="..."
Width="300"
Height="300" />
</Canvas>
The zoom code:
var matrix = ((MatrixTransform)m_image.RenderTransform).Matrix;
var center = new Point(m_image.ActualWidth / 2, m_image.ActualHeight / 2);
center = matrix.Transform(center);
matrix.ScaleAt(delta.Scale.X, delta.Scale.Y, center.X, center.Y);
((MatrixTransform)m_image.RenderTransform).Matrix = matrix;
The problem is that when I'm zooming the image render size go larger that the canvas limit (300x300). I would like if the image can zoom only in the canvas.
I don't want to limit the max zoom, I want that if the render size of the image is larger that the canvas, it's stay inside. I don't want that it overlap the canvas
You could clip to the bounds of the Canvas:
<Canvas ClipToBounds="True" ...>
But I don't understand why you're using a Canvas in the first place. It's likely that there's a much nicer way to approach your particular problem without the need for hard-coded widths and heights and without any Canvas at all.
Related
I have a rectangle on a canvas that the user can resize, move and so on to make a selection.
I also have an image the size of the screen behind the canvas (basically a screenshot).
I'd like to translate the selection (the rectangle) in the canvas to a 1:1 selection in the image (I want the image directly behind the rectangle) given I have the rectangle's Canvas.Top, Canvas.Left, Width, Height.
<Grid Name="MainGrid" SnapsToDevicePixels="False" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<Image x:Name="MainImage" Stretch="None" RenderOptions.BitmapScalingMode="HighQuality"/>
<Border Background="Black" Opacity="0.4" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
<Canvas Name="MainCanvas" Width="{Binding Source={x:Static SystemParameters.PrimaryScreenWidth}}" Height="{Binding Source={x:Static SystemParameters.PrimaryScreenHeight}}" Background="Transparent">
<ContentControl Name="SelectionRect" />
</ContentControl>
</Canvas>
</Grid>
I tried doing this: (MainImage is the image under the canvas)
Rect rect = new Rect(Canvas.GetLeft(SelectionRect), Canvas.GetTop(SelectionRect), SelectionRect.Width, SelectionRect.Height);
Rect from_rect = SelectionRect.TransformToVisual(this).TransformBounds(rect);
BitmapSource cropped_bitmap = new CroppedBitmap(MainImage.Source as BitmapSource,
new Int32Rect((int)from_rect.X, (int)from_rect.Y, (int)from_rect.Width, (int)from_rect.Height));
SelectionRectImageSource = cropped_bitmap;
But the image I get (SelectionRectImageSource) is a moved aside version of the actual pixels behind the selection rectangle.
So basically, I don't understand how these transformations work and how I should use them if at all.
Example:
Thanks a lot!
Dolev.
Looks like you need to correct for the DPI difference between the image (usually 72dpi) and the presentation source (usually 96dpi). Additionally, your first Rect should not be offset by Canvas.Left and Canvas.Top; TransformToVisual will take care of the relative offset for you.
var source = (BitmapSource)MainImage.Source;
var selectionRect = new Rect(SelectionRect.RenderSize);
var sourceRect = SelectionRect.TransformToVisual(MainImage)
.TransformBounds(selectionRect);
var xMultiplier = source.PixelWidth / MainImage.ActualWidth;
var yMultiplier = source.PixelHeight / MainImage.ActualHeight;
sourceRect.Scale(xMultiplier, yMultiplier);
var croppedBitmap = new CroppedBitmap(
source,
new Int32Rect(
(int)sourceRect.X,
(int)sourceRect.Y,
(int)sourceRect.Width,
(int)sourceRect.Height));
SelectionRectImageSource= croppedBitmap;
Depending on where this code resides, you may also need to transform the selection rectangle to MainImage instead of this (as I did).
Also, in case MainImage.Source is smaller than the actual MainImage control, you should probably set the horizontal and vertical alignments of MainImage to Left and Top, respectively, less your translated rectangle end up outside the bounds of the source image. You'll need to clamp the selection rectangle to the dimensions of MainImage too.
This my first post on stack overflow, I hope I get it right. I am using the ZoomControl from WPF Extensions to display an image with pan and zoom support:
<DockPanel Grid.Row="1" x:Name="canvas">
<Controls:ZoomControl x:Name="zoomControl">
<Canvas x:Name="canvas">
<Image x:Name="imageControl" Stretch="None" />
</Canvas>
</Controls:ZoomControl>
</DockPanel>
When the user selects an image with a bowse dialog, I load that image like so:
bmp = new BitmapImage(new Uri(fileName));
this.imageControul.Source = bmp;
I would like to added rectangles\adorners to specific locations (pixel coordinates) on the image the user loaded based on some image processing.
var r = new Rectangle();
r.StrokeThickness = 5;
r.Stroke = Brushes.Black;
r.Fill = Brushes.Transparent;
r.Width = width;
r.Height = height;
Canvas.SetLeft(r, y);
Canvas.SetTop(r, x);
canvas.Children.Add(r);
However, the rectangles are not placed in the expected locations? Wrong scale and location.
Thanks,
John
I expect the problem is that your Canvas is expanding to fill the space rather than being locked to the rectangle. Have a look with a tool like Snoop and see what the bounding boxes of the two are.
You might be able to fix it with Horizontal and VercticalAlignment on the canvas, set them to anything other than Stretch.
If that doesn't work restructure it like this
<ZoomBox>
<Grid>
<Image/>
<Canvas/>
</Grid>
</ZoomBox>
So the Image and the canvas are grouped by the parent Grid which is being transformed.
I am trying to zoom in and out image inside Rectangle control. But while doing so my entire Rectangle is getting zoomed in instead of just image inside that. for doing so I am using ScaleTransform and TranslateTranform on Rectangle. I should do the same on image instead of Rectangle but I dont know how? Could anyone please help me out.
XAML :
<Rectangle x:Name="LiveViewWindow" Fill="#FFF4F4F5" HorizontalAlignment="Right"
ClipToBounds="True" />
Code:
InteropBitmap m_LiveViewBitmapSource =Imaging.CreateBitmapSourceFromMemorySection(
section, width, height, PixelFormats.Bgr32, width*4, 0) as InteropBitmap;
ImageBrush m_BackgroundFrame = new ImageBrush(m_LiveViewBitmapSource);
RenderOptions.SetBitmapScalingMode(m_BackgroundFrame, BitmapScalingMode.LowQuality);
LiveViewWindow.Fill = m_BackgroundFrame;
n then for I am using Invalidate() property to render InteropBitmap to Rectangle.
You may set the Transform property of the ImageBrush. Get more information in Brush Transformation Overview.
I wish to display a HD size 1920X1080 image in my WPF application. When I set the image source in the image control, only part of the image is displayed, size of image control.
I do not wish to auto-fit the HD image into the image control. Say the image control is size 640 X 480 then the 640X480 of HD image should be displayed. But when I pan the image then the next 640 X 480 of the image should be displayed.
I already have implemented TransformGroup
TransformGroup group = new TransformGroup();
ScaleTransform xform = new ScaleTransform();
group.Children.Add(xform);
TranslateTransform tt = new TranslateTransform();
group.Children.Add(tt);
But my problem is that entire image is not loaded initially.
If all you want is the ability to scroll your image...then use:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<ScrollViewer HorizontalScrollBarVisibility="Visible">
<Image Stretch="None" Source="c:\mytestimage.png" />
</ScrollViewer>
</Grid>
</Window>
See these handy posts if you want to be more sophisticated/efficient:
WPF Image Zooming
Pan & Zoom Image
http://www.codeproject.com/Articles/85603/A-WPF-custom-control-for-zooming-and-panning
There is an alternate way to display the image. Set the max-es on the image, so it wont visually load larger than what is needed.
<Image Source="{Binding Source}"
Stretch="UniformToFill"
MaxHeight="200"
MaxWidth="400"/>
Image below shows two images loaded as is, a small one and a large one. The left side shows the large one exploding past the boundaries. The right one shows the proper shrinkage for the large one.
To keep the smaller image from oversizing (as shown on the right side) set the StretchDirection="DownOnly" to keep the smaller one from expanding.
I am currently designing a layout app in Silverlight and have a Canvas inside of a Viewbox. I add shapes to the canvas and they display properly, when I resize the viewbox to zoom in at 2x the height and width, everything still draws properly.
The problem comes when I try to zoom at a factor of 4 or greater or at 0.5 (zoomed out).
Update: The horizontal lines are still there, they are just not drawing. Interaction between the the other shapes and the disappearing ones is still present
When I do this, any horizontal lines do not redraw, but any other shapes, vertical lines of other, still redraw fine. The objects are still children of the canvas and their visibilities are all set to visible.
What is happening?
Update
Very Simple XAML:
<ScrollViewer x:Name="scrollViewer"
Padding="0"
ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollBarVisibility="Auto"
IsTabStop="False"
Background="Beige">
<Viewbox x:Name="viewBox" Stretch="UniformToFill">
<Canvas x:Name="designCanvas"
Background="{Binding ElementName=mainControl, Path=Background, Mode=TwoWay}">
</Canvas>
</Viewbox>
</ScrollViewer>
Here is how I add the shapes:
Rectangle horGuide = new Rectangle()
{
Tag = "horGuide",
Fill = new SolidColorBrush(Colors.Cyan),
Height = 0.5,
Width = designCanvas.canvActualWidth*16,
};
int h = designCanvas.horOffset;
int v = designCanvas.vertOffset;
double d = e.GetPosition(sideRule).Y;
designCanvas.Children.Add(horGuide);
Canvas.SetTop(horGuide, ((d+v )/ designCanvas.zoomFactor));
Canvas.SetLeft(horGuide, 0 - h);
To Zoom in:
viewBox.Width *= 2;
viewBox.Height *= 2;
Why not use the ScaleTransform class to zoom in and out.