I have created a custom control that simply draws a grid of squares on the screen. To do this it overrides the OnRender method and draws rectangles.
I have added this custom control to a WPF window. However when I resize the window, part of the custom control is hidden. What I want to happen is a scroll bar appears, however after adding a scroll viewer it hasn't done anything.
I have read elsewhere I should implementent IScrollInfo, but that seems like a lot of effort to do something quite simple.
If anyone could help me out it would be greatly appreciated.
Many thanks,
Matt
A ScrollViewer can scroll any arbitrary content so you don't need to implement IScrollInfo unless you want to support logical scrolling, i.e. by lines instead of by pixels.
Unless your custom control implements MeasureOverride it won't participate in the measure phase of layout and a ScrollViewer won't know big you want the scrollable region to be.
Here is a comple XAML-only example of a scrollable Grid with a graph paper background:
<DockPanel>
<ScrollViewer Height="200" Width="250" HorizontalScrollBarVisibility="Visible">
<Grid Height="400" Width="400">
<Grid.Background>
<DrawingBrush x:Name="GridBrush"
Viewport="0,0,10,10" ViewportUnits="Absolute" TileMode="Tile">
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="#CCCCFF">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0 10,1" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing Brush="#CCCCFF">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0 1,10" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Grid.Background>
</Grid>
</ScrollViewer>
</DockPanel>
The ScrollViewer will use its child's DesiredSize as a determinant for whether scrolling is necessary. Does your custom control override Measure()? Posting the code for your custom control will likely be required to help further.
Related
I would like to use Visual Studio 2022 Image Library in my project. The one that the VS2022 IDE uses (surprise!). But when I add an icon to a menu item, it doesn't look as pretty as it does in a VS menu:
<MenuItem.Icon>
<Rectangle Width="16" Height="16">
<Rectangle.Fill>
<DrawingBrush>
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="{DynamicResource canvas}" Geometry="F1M16,16H0V0H16Z" />
<DrawingGroup Opacity="{DynamicResource cls-1}">
<GeometryDrawing Brush="{DynamicResource light-defaultgrey-10}" Geometry="F1M14.5,4.5v10H3.5V7.95A4.984,4.984,0,0,0,8,3a4.966,4.966,0,0,0-.254-1.5H11.5Z" />
<GeometryDrawing Brush="{DynamicResource light-defaultgrey}" Geometry="F1M15,4.5v10l-.5.5H3.5L3,14.5V8a4.988,4.988,0,0,0,1-.1V14H14V5H11V2H7.9a4.968,4.968,0,0,0-.321-1H11.5l.354.146,3,3Z" />
</DrawingGroup>
<GeometryDrawing Brush="{DynamicResource light-yellow}" Geometry="F1M3,2,3,0H4L4,2l-.5.5Zm.5,2.5L3,5V7H4V5Zm1-1L5,4,7,4V3L5,3Zm-2,0L2,3,0,3V4L2,4Zm1.708-.7h.708L6.328,1.378,5.62.671,4.208,2.088ZM2.792,4.206H2.085L.673,5.623l.707.706L2.793,4.913Zm1.414,0v.708L5.623,6.328l.706-.708L4.913,4.208ZM2.794,2.792V2.085L1.378.673.671,1.38,2.088,2.793Z" />
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Rectangle.Fill>
</Rectangle>
</MenuItem.Icon>
Compare the IDE's and my renders (scaled):
As you can see, my icons seem to be shifted horizontally by a fraction of a pixel. Perhaps it's just because Microsoft guys used PNG instead of XAML.
I've tried adding SnapsToDevicePixels wherever possible, but it doesn't change anything. Obviously, specifying a correct offset will be enough for the solution, but I don't know that offset. And I don't want to look through the Magnifier every time I add a new icon to make sure I need to subtract a hundredth of a pixel from the offset I guessed.
Could you suggest an elegant solution to removing the subpixel effect when rendering these XAML icons?
How do I set the absolute position of a GeometryDrawing?
Currently the line is always drawn in the center.
I guess the LineGeometery is always following the Alignments on Image control.
Here is some (now edited) code I am working with:
<Window x:Class="WpfProblem.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" >
<Grid Width="450" Height="160" Background="Beige" VerticalAlignment="Stretch">
<Border BorderBrush="Lime" BorderThickness="1" CornerRadius="80" Background="#1AFF0000" Margin="0">
<Image Width="420" Height="120" Stretch="None" >
<Image.Source>
<DrawingImage>
<DrawingImage.Drawing>
<GeometryDrawing>
<GeometryDrawing.Geometry>
<LineGeometry StartPoint="0,30" EndPoint="299,30"/>
</GeometryDrawing.Geometry>
<GeometryDrawing.Pen>
<Pen Thickness="5" Brush="Black"/>
</GeometryDrawing.Pen>
</GeometryDrawing>
</DrawingImage.Drawing>
</DrawingImage>
</Image.Source>
</Image>
</Border>
</Grid>
</Window>
I believe that your problem (aside from the code above that does not compile, since Image.Source does not have Width and Height attributes) isn't that your GeometryDrawing is centered, it's that your Canvas is centered.
To prove it, just make the Background of your Canvas Red:
<Canvas Width="350" Height="180" Background="Red">
Your GeometryDrawing is at the appropriate position within this centered Canvas.
If you want the Canvas to fit the entire window, don't set explicit width and height, set HorizontalAlignment and VerticalAlignment to Stretch:
<Canvas HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Background="Blue">
to get:
It looks like Vertical & HorizontalAlignment affects the internal drawing of a DrawImage. So depending on VerticalAlignment, a single horizontal line will be drawn at the top, center, or bottom of the final Image. I am now embedding the Drawing in a FrameworkElement with the needed absolute positioning.
Corrected per Liz's comment.
If you change Stretch="None" to Stretch="Fill" on your Image it will use the whole space. It won't fill up the whole size of the border, because you have specified a height and width.
Now if you use a GeometryGroup you can specify as many types of lines, paths, whatever. This will then be stretched to fill your image space.
<GeometryGroup>
<LineGeometry StartPoint="0,0" EndPoint="410,0"/>
<LineGeometry StartPoint="0, 100" EndPoint="410, 0"/>
</GeometryGroup>
The lines will be drawn to "fit" your image.
Which is a little closer to what you want, I think. Leaving the the Stretch to None, will draw the objects at the center of the image, and will not stretch them when the image is re-sized.
That seems to be the two alternatives of using the ImageDrawing, either center, or draw to fit.
Here's an example image of what I mean: example
The gray rectangle is the bounding box of a control that draws the blue lines and dots in it's OnRender(...) method. The red ovals mark places where it happens.
Why is that possible?
How can it be avoided?
Here's the perfect answer to my second question, at least when using a rectangular shaped control:
<object ClipToBounds="True" />
More details on the MSDN.
https://msdn.microsoft.com/en-us/library/ms750441(v=vs.100).aspx has detailed information about the architectural design of WPF to answer why it is possible.
To avoid it you want to use the clip property of your element.
<Rectangle Fill="Yellow" Height="100" Width="200" StrokeThickness="2" Stroke="Black">
<Rectangle.Clip>
<EllipseGeometry Center="200,100" RadiusX="50" RadiusY="50" />
</Rectangle.Clip>
</Rectangle>
Check out http://msdn.microsoft.com/en-us/library/cc189065%28v=VS.95%29.aspx for more details.
Suppose I need to set an opacity mask on a WPF control that highlights a portion of it in precise position (suppose a 50x50 square at (50;50) position). To do that I create a DrawingGroup containing 2 GeometryDrawing objects: 1 semi-transparent rectangle for the whole actual size of the control and 1 opaque rectangle for highlighted area. Then I create a DrawingBrush from this DrawingGroup, set it's Stretch property to None and set this brush as OpacityMask of the control that needs to be masked.
All this works fine while nothing is "sticking" out of bounds of said control. But if control draws something outside of it's bounds the outer point becomes a starting point from where opacity mask is applied (if the brush is aligned to that side) and the whole mask shifts by that distance resulting in unexpected behavior.
I can't seem to find a way to force mask to be applied from control's bounds or at least get the actual bounds of the control (including sticking parts) so I can adjust my mask accordingly.
Any ideas highly appreciated!
Update: Here's a simple test-case XAML and screenshots demonstrating the issue:
We have 2 nested Borders and Canvas in the last one with the above mentioned square:
<Border Padding="20" Background="DarkGray" Width="240" Height="240">
<Border Background="LightBlue">
<Canvas>
<Rectangle Canvas.Left="50" Canvas.Top="50" Width="50" Height="50"
Stroke="Red" StrokeThickness="2"
Fill="White"
/>
</Canvas>
</Border>
</Border>
Here's how it looks:
(source: ailon.org)
Now we add an OpacityMask to the second border so that every part of it except our square is semi-transparent:
<Border.OpacityMask>
<DrawingBrush Stretch="None" AlignmentX="Left" AlignmentY="Top">
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="#30000000">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0,200,200" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing Brush="Black">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="50,50,50,50" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Border.OpacityMask>
Everything looks as expected:
(source: ailon.org)
And now we add a line to the canvas that sticks 10 pixels out on the left of our border:
<Line X1="-10" Y1="150" X2="120" Y2="150"
Stroke="Red" StrokeThickness="2"
/>
And the mask shifts 10 pixels to the left:
(source: ailon.org)
Update2: As a workaround I add a ridiculously large transparent rectangle outside of bounds and adjust my mask accordingly but that is a really nasty workaround.
Update3: Note: The canvas with rectangle and line is there just as an example of some object that has something outside of it bounds. In context of this sample it should be treated as some sort of a black box. You can't change it's properties to solve the general issue. This would be the same as just moving the line so it doesn't stick out.
Interesting issue indeed - here's what I've figured: The effect you are experiencing seems to be determined by the Viewport concept/behavior of TileBrush (see Viewbox too for the complete picture). Apparently the implicit bounding box of a FrameworkElement (i.e. the Canvas in your case) is affected/expanded by elements sticking out of bounds in a subtle way, that is, the dimensions of the box expand but the coordinate system of the box does not scale, rather expands too into the out of bounds direction.
It might be easier to illustrate that graphically, but due to time constraints I'll just offer a solution first and will explain the steps I've taken for the moment in order to get you started:
Solution:
<Border Background="LightBlue" Width="198" Height="198">
<Border.OpacityMask>
<DrawingBrush Stretch="None" AlignmentX="Center" AlignmentY="Center"
Viewport="-10,0,222,202" ViewportUnits="Absolute">
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="#30000000">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="-10,0,220,200" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing Brush="Black">...</GeometryDrawing>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Border.OpacityMask>
<Canvas x:Name="myGrid">...</Canvas>
</Border>
Please note that I've adjusted units by +/- 2 pixels here and there for pixel precision without knowing where the offset originates, but I think this can be ignored for the purpose of the example and resolved later if need be.
Explanation:
To simplify the illustration one should usually make all related implied/auto properties explicit first.
The inner border receives auto dimensions of 198 from the outer border (240 - 20 padding - 2 pixels deduced by experiment; don't know their origin, but ignorable right now), that is if you specify this as follows nothing should change, while using other values yields graphical changes:
<Border Background="LightBlue" Width="198" Height="198">...</Border>
Further the default implied Viewport and ViewportUnits like so:
<DrawingBrush Stretch="None" AlignmentX="Left" AlignmentY="Top"
Viewport="0,0,1,1" ViewportUnits="RelativeToBoundingBox">...</DrawingBrush>
You are enforcing the DrawingBrush size by overriding Stretch with None, while keeping the position and dimension of the base tile at default and relative to its bounding box. In addition you (understandably) are overriding AlignmentX/AlignmentY, which determine the placement within the base tile, that is within its bounding box. Resetting those to their defaults of Center is already telling: The mask shifts accordingly, meaning it has to be smaller than the bounding box, else their would be nothing to center within.
This can be taken further by changing ViewportUnits to Absolute, which will yield no graphics at all until the units are properly adjusted of course; again, by experiment the following explicit values are matching the auto ones, while using other values yields graphical changes:
<DrawingBrush Stretch="None" AlignmentX="Center" AlignmentY="Center"
Viewport="0,0,202,202" ViewportUnits="Absolute">...</DrawingBrush>
Now the opacity mask already aligns properly with the control. Obviously there is one problem left though, as the mask is clipping the line now, which is no surprise given its size and the absence of any Stretch effect. Adjusting its size and position accordingly resolves this:
<RectangleGeometry Rect="-10,0,220,200" />
and
<DrawingBrush Stretch="None" AlignmentX="Center" AlignmentY="Center"
Viewport="-10,0,222,202" ViewportUnits="Absolute">...</DrawingBrush>
Finally the opacity mask matches the control bounds as desired!
Supplement:
The required offsets determined by deduction and experiment in the explanation above can be retrieved at runtime by means of the VisualTreeHelper Class:
Rect descendantBounds = VisualTreeHelper.GetDescendantBounds(myGrid);
Depending on your visual element composition and needs you may need to factor in the LayoutInformation Class and build the union of both to get the all-encompassing bounding box:
Rect descendantBounds = VisualTreeHelper.GetDescendantBounds(myGrid);
Rect layoutSlot = LayoutInformation.GetLayoutSlot(myGrid);
Rect boundingBox = descendantBounds;
boundingBox.Union(layoutSlot);
See the following links for more details on both topics:
Windows Presentation Foundation
Graphics Rendering Overview,
especially VisualTreeHelper
Class
The Layout System, especially
Element Bounding Boxes
On your Canvas object add ClipToBounds="True".
<Canvas ClipToBounds="True">
<Rectangle Canvas.Left="50" Canvas.Top="50" Width="50" Height="50"
Stroke="Red" StrokeThickness="2"
Fill="White" />
<Line X1="-10" Y1="150" X2="120" Y2="150"
Stroke="Red" StrokeThickness="2"/>
</Canvas>
One workaround that may be more ideal than your current one would be to simply apply the OpacityMask at a higher level. Using this demo code for example, you could remove the mask from the Border and apply it to the Window instead. With a bit of tweaking it fits properly:
<Window.OpacityMask>
<DrawingBrush AlignmentX="Left" AlignmentY="Top" Stretch="None">
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="#30000000">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0,300,300"/>
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing Brush="Black">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="92,82,50,50"/>
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Window.OpacityMask>
You would have to write some code to move the mask when the Window is resized, and for that reason you may be better off generating the mask dynamically in the code-behind.
My question for you is, why do you need to handle geometries that go outside the bounds of your Canvas?
Since you have parts that stick out from the control, one idea is to separate control image from the control mask.
<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Border Padding="20" Background="DarkGray" Width="240" Height="240"> <!-- user container -->
<Grid> <!-- the control -->
<Border Background="LightBlue" HorizontalAlignment="Stretch"> <!-- control mask-->
<Canvas>
<Rectangle Canvas.Left="50" Canvas.Top="50" Width="50" Height="50"
Stroke="Red" StrokeThickness="2"
Fill="White"
/>
<Canvas.OpacityMask>
<DrawingBrush Stretch="None" AlignmentX="Left" AlignmentY="Top" TileMode="None">
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="#30000000">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0,200,200" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing Brush="Black">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="50,50,50,50" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Canvas.OpacityMask>
</Canvas>
</Border>
<Canvas> <!-- control image-->
<Line X1="-10" Y1="150" X2="120" Y2="150" Stroke="Red" StrokeThickness="2"/>
</Canvas>
</Grid>
</Border>
</Window>
I have a window with these values:
WindowState="Maximized"
AllowsTransparency="True"
Opacity="0.5"
WindowStyle="None"
This window is coming on top of other window (as a pop-up) with content on it on a specific location.
I have a new requirement. This window have to show a rectangle area from the window below. In other words, i have to set a "hole" in this window which will be totally transparent (without the opacity value).
Until this moment i couldn't figure out a way to make this transparent hole.
Hope to get an idea...
I found a kind of solution for it:
this is the pop-up window that on top of another window, and containing a hole to the other window in a desired place:
Window's header:
WindowState="Maximized"
AllowsTransparency="True"
WindowStyle="None"
Window's content:
<Window.Background >
<SolidColorBrush x:Name="BackgroundBrush" Color="WhiteSmoke" Opacity="0" ></SolidColorBrush>
</Window.Background>
<Canvas x:Name="ContectHolder" >
<Path Stroke="Black" Fill="WhiteSmoke" Opacity="0.8">
<Path.Data>
<CombinedGeometry GeometryCombineMode="Exclude">
<CombinedGeometry.Geometry1 >
<RectangleGeometry Rect="0,0,2000,2000" />
</CombinedGeometry.Geometry1>
<CombinedGeometry.Geometry2>
<RectangleGeometry Rect="75,75,400,900" />
</CombinedGeometry.Geometry2>
</CombinedGeometry>
</Path.Data>
</Path>
</Canvas>
try to avoid AllowsTransparency=true, it is very buggy and slow.
you can PInvoke SetWindowRgn to create a a window of any shape:
Use CreateRectRgn twice, once for the window bounding rectangle and once for the hole.
Use CombineRgn with RGN_AND as the 4th parameter to get a region with an hole in it
Call SetWindowRgn to apply the region to the window
Don't forget to delete all the regions except for the one you passed to SetWindowRgn