Simple problem.
I have a form to which I add a panel and put 1 label with some text. When I look at the saved image, all I see is the panel. I have tried all the solutions I could find. Code below. I get the panel saved but the text box doesn't appear. If I can get that to work, then I can do all that I need.
What am I doing wrong?
int x = SystemInformation.WorkingArea.X;
int y = SystemInformation.WorkingArea.Y;
int width = printPanel.Width;
int height = printPanel.Height;
Rectangle bounds = new Rectangle(x, y, width, height);
using (Bitmap flag = new Bitmap(width, height))
{
printPanel.DrawToBitmap(flag, bounds);
if (Environment.UserName == "grimesr")
{
string saveImage = Path.Combine(fileStore, "./p" + ".png");
flag.Save(saveImage);
}
}
Really not sure where you're going wrong.
Here's a simple test:
private void button1_Click(object sender, EventArgs e)
{
int width = printPanel.Width;
int height = printPanel.Height;
Rectangle bounds = new Rectangle(0, 0, width, height);
Bitmap flag = new Bitmap(width, height);
printPanel.DrawToBitmap(flag, bounds);
pictureBox1.Image = flag;
}
It grabs the entire panel and puts the image into the picturebox to the right:
Thanks for the hints, even if they weren't directly related. The print button helped me figure this out. The button code worked as desired. However, putting the same code where I had it wasn't working. I then noticed a InvalidOperation error was being rasied. So looking at more in detail led me to see what the real issue was.
I must admit I left out 1 tiny piece of information that was critical. I was trying to do this in a thread that was feeding my label printer. Of course, trying to used a UI panel control in the thread threw an Invalid Operation. I moved the code out and all is well now. Cross thread operations are sometimes subtle and difficult to think about how they fail.
Problem solved for me.
Related
I am trying to draw multiple lines on a winforms panel using it's graphics object in paint event. I am actually drawing a number of lines joining given points. So, first of all I did this,
private void panel1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawLines(new Pen(new SolidBrush(Color.Crimson), 3), PointFs.ToArray());
float width = 10;
float height = 10;
var circleBrush = new SolidBrush(Color.Crimson);
foreach (var point in PointFs)
{
float rectangleX = point.X - width / 2;
float rectangleY = point.Y - height / 2;
var r = new RectangleF(rectangleX, rectangleY, width, height);
e.Graphics.FillEllipse(circleBrush, r);
}
}
Which produces a result like the image below,
As you can see lines are drawn with having a little bit of extension at sharp turns, which is not expected. So, I changed the drawlines code to,
var pen = new Pen(new SolidBrush(Color.Crimson), 3);
for (int i = 1; i < PointFs.Count; i++)
{
e.Graphics.DrawLine(pen, PointFs[i - 1], PointFs[i]);
}
And now the drawing works fine.
Can anyone tell the difference between the two approaches?
I have just had the same problem (stumbled upon this question during my research), but I have now found the solution.
The problem is caused by the LineJoin property on the Pen used. This DevX page explains the different LineJoin types (see Figure 1 for illustrations). It seems that Miter is the default type, and that causes the "overshoot" when you have sharp angles.
I solved my problem by setting the LineJoin property to Bevel:
var pen = new Pen(new SolidBrush(Color.Crimson), 3);
pen.LineJoin = Drawing2D.LineJoin.Bevel;
Now DrawLines no longer overshoot the points.
I'm looking to create a scrolling surfacelistbox which automatically snaps into a position after a drag is finished so that the center item on the screen is centered itself in the viewport.
I've gotten the center item, but now as usual the way that WPF deals with sizes, screen positions, and offsets has me perplexed.
At the moment I've chosen to subscribe to the SurfaceScrollViewer's ManipulationCompleted event, as that seems to consistently fire after I've finished a scroll gesture (whereas the ScrollChanged event tends to fire early).
void ManipCompleted(object sender, ManipulationCompletedEventArgs e)
{
FocusTaker.Focus(); //reset focus to a dummy element
List<FrameworkElement> visibleElements = new List<FrameworkElement>();
for (int i = 0; i < List.Items.Count; i++)
{
SurfaceListBoxItem item = List.ItemContainerGenerator.ContainerFromIndex(i) as SurfaceListBoxItem;
if (ViewportHelper.IsInViewport(item) && (List.Items[i] as string != "Dummy"))
{
FrameworkElement el = item as FrameworkElement;
visibleElements.Add(el);
}
}
int centerItemIdx = visibleElements.Count / 2;
FrameworkElement centerItem = visibleElements[centerItemIdx];
double center = ss.ViewportWidth / 2;
//ss is the SurfaceScrollViewer
Point itemPosition = centerItem.TransformToAncestor(ss).Transform(new Point(0, 0));
double desiredOffset = ss.HorizontalOffset + (center - itemPosition.X);
ss.ScrollToHorizontalOffset(desiredOffset);
centerItem.Focus(); //this also doesn't seem to work, but whatever.
}
The list snaps, but where it snaps seems to be somewhat chaotic. I have a line down the center of the screen, and sometimes it looks right down the middle of the item, but other times it's off to the side or even between items. Can't quite nail it down, but it seems that the first and fourth quartile of the list work well, but the second and third are progressively more off toward the center.
Just looking for some help on how to use positioning in WPF. All of the relativity and the difference between percentage-based coordinates and 'screen-unit' coordinates has me somewhat confused at this point.
After a lot of trial and error I ended up with this:
void ManipCompleted(object sender, ManipulationCompletedEventArgs e)
{
FocusTaker.Focus(); //reset focus
List<FrameworkElement> visibleElements = new List<FrameworkElement>();
for (int i = 0; i < List.Items.Count; i++)
{
SurfaceListBoxItem item = List.ItemContainerGenerator.ContainerFromIndex(i) as SurfaceListBoxItem;
if (ViewportHelper.IsInViewport(item))
{
FrameworkElement el = item as FrameworkElement;
visibleElements.Add(el);
}
}
Window window = Window.GetWindow(this);
double center = ss.ViewportWidth / 2;
double closestCenterOffset = double.MaxValue;
FrameworkElement centerItem = visibleElements[0];
foreach (FrameworkElement el in visibleElements)
{
double centerOffset = Math.Abs(el.TransformToAncestor(window).Transform(new Point(0, 0)).X + (el.ActualWidth / 2) - center);
if (centerOffset < closestCenterOffset)
{
closestCenterOffset = centerOffset;
centerItem = el;
}
}
Point itemPosition = centerItem.TransformToAncestor(window).Transform(new Point(0, 0));
double desiredOffset = ss.HorizontalOffset - (center - itemPosition.X) + (centerItem.ActualWidth / 2);
ss.ScrollToHorizontalOffset(desiredOffset);
centerItem.Focus();
}
This block of code effectively determines which visible list element is overlapping the center line of the list and snaps that element to the exact center position. The snapping is a little abrupt, so I'll have to look into some kind of animation, but otherwise I'm fairly happy with it! I'll probably use something from here for animations: http://blogs.msdn.com/b/delay/archive/2009/08/04/scrolling-so-smooth-like-the-butter-on-a-muffin-how-to-animate-the-horizontal-verticaloffset-properties-of-a-scrollviewer.aspx
Edit: Well that didn't take long. I expanded the ScrollViewerOffsetMediator to include HorizontalOffset and then simply created the animation as suggested in the above post. Works like a charm. Hope this helps someone eventually.
Edit2: Here's the full code for SnapList:
SnapList.xaml
SnapList.xaml.cs
Note that I got pretty lazy as this project went on an hard-coded some of it. Some discretion will be needed to determine what you do and don't want from this code. Still, I think this should work pretty well as a starting point for anyone who wants this functionality.
The code has also changed from what I pasted above; I found that using Windows.GetWindow gave bad results when the list was housed in a control that could move. I made it so you can assign a control for your movement to be relative to (recommended that be the control just above your list in the hierarchy). I think a few other things changed as well; I've added a lot of customization options including being able to define a custom focal point for the list.
I've got a custom (and getting complex) TabControl. It's a gathering of many sources, plus my own wanted features. In it is a custom Panel to show the headers of the TabControl. Its features are to compress the size of the TabItems until they reached their minimum, and then activates scrolling features (in the Panel, again). There is also another custom panel to hold a single button, that renders on the right of the TabItems (it's a "new tab" button).
It all works great, until I try to animate the scrolling.
Here are some relevant snippets :
In the CustomTabPanel (C#, overriding Panel and implementing IScrollInfo):
private readonly TranslateTransform _translateTransform = new TranslateTransform();
public void LineLeft()
{
FirstVisibleIndex++;
var offset = HorizontalOffset + _childRects[0].Width;
if (offset < 0 || _viewPort.Width >= _extent.Width)
offset = 0;
else
{
if (offset + _viewPort.Width > _extent.Width)
offset = _extent.Width - _viewPort.Width;
}
_offset.X = offset;
if (_scrollOwner != null)
_scrollOwner.InvalidateScrollInfo();
//Animate the new offset
var aScrollAnimation = new DoubleAnimation(_translateTransform.X, -offset,
new Duration(this.AnimationTimeSpan), FillBehavior.HoldEnd) { AccelerationRatio = 0.5, DecelerationRatio = 0.5 };
aScrollAnimation.Completed += ScrollAnimationCompleted;
_translateTransform.BeginAnimation(TranslateTransform.XProperty, aScrollAnimation , HandoffBehavior.SnapshotAndReplace);
//End of animation
// These lines are the only ones needed if we remove the animation
//_translateTransform.X = -offset;
//InvalidateMeasure();
}
void ScrollAnimationCompleted(object sender, EventArgs e)
{
InvalidateMeasure();
}
the _translateTransform is initialized in the constructor :
base.RenderTransform = _translateTransform;
Again, everything is fine if I remove the animation part and just replace it with the commented out lines at the end.
I must also point out that the problem is NOT with the animation itself. That part works out well. The problem is about when I remove some tab items : all the layout then screws up. The TranslateTransformation seems to hold on some wrong value, or something.
Thanks in advance.
Well. As it's often the case, I kept working on the thing, and... answered myself.
Could still be useful for other people, so here was the catch. In the line :
var aScrollAnimation = new DoubleAnimation(_translateTransform.X, -offset, new Duration(this.AnimationTimeSpan), FillBehavior.HoldEnd)
{ AccelerationRatio = 0.5, DecelerationRatio = 0.5 };
the FillBehavior should have been FillBehavior.Stop.
As easy as that!
I want to change the direction of my marquee on changeDirection button click.
My code for changing direction is :
private void changeDirection_click(object sender, RoutedEventArgs e)
{
if (_marqueeType == MarqueeType.RightToLeft)
{
_marqueeType = MarqueeType.LeftToRight;
StartMarqueeing(_marqueeType);
}
else if (_marqueeType == MarqueeType.LeftToRight)
{
_marqueeType = MarqueeType.RightToLeft;
StartMarqueeing(_marqueeType);
}
}
And code for start marquee is :
public void StartMarqueeing(MarqueeType marqueeType)
{
double height = canMain.ActualHeight - marqueeList.ActualHeight;
marqueeList.Margin = new Thickness(0, 0, 0, 0);
doubleAnimation.From = -marqueeList.ActualWidth;
doubleAnimation.To = canMain.ActualWidth;
doubleAnimation.RepeatBehavior = RepeatBehavior.Forever;
doubleAnimation.Duration = new Duration(TimeSpan.FromSeconds(_marqueeTimeInSeconds));
if (marqueeType == MarqueeType.RightToLeft)
{
Storyboard.SetTargetProperty(doubleAnimation, new PropertyPath("(Canvas.Right)"));
_storyBoard.Children.Add(doubleAnimation);
_storyBoard.Begin(marqueeList, true);
}
else if (marqueeType == MarqueeType.LeftToRight)
{
Storyboard.SetTargetProperty(doubleAnimation, new PropertyPath("(Canvas.Left)"));
_storyBoard.Children.Add(doubleAnimation);
_storyBoard.Begin(marqueeList, true);
}
}
Now here I am able to change the direction from Right to Left only first time.
But when I am change it from Left to Right it’s not changing the marquee position Left to Right.
It looks like you left out a _storyboard = new Storyboard(), perhaps at the top of the StartMarqueeing method.
From what I see it appears that every call to StartMarqueeing will add an additional DoubleAnimation to the storyboard, then start it again. So all the old DoubleAnimations will be recreated, and it looks like they take precedence.
Try creating a new Storyboard object each time, not just re-using it and adding to its children collection.
Update
Oh, now I see the problem. You should not be setting both (Canvas.Left) and (Canvas.Right). Use only one of the two: That's all you need anyway, and using both will give the Canvas conflicting instructions. Traditionally people use (Canvas.Left). I think that's what Canvas selects, which is what is causing your asymmetry.
You may wonder why I say you are using both when you don't think your two animations every run at the same time. Actually they do: The first animation runs then holds the value on the animated property until it is removed or bumped off by another animation. If the second animation then runs and modifies a different property it doesn't bump off the first animation so the first animation's value is still present.
The bottom line is, using (Canvas.Left) on both animations should fix it as long as you are using the default HandoffBehavior.SnapshotAndReplace.
GDI+ DrawLines function has a clipping bug that can be reproduced by running the following c# code. When running the code, two line paths appear, that should be identical, because both of them are inside the clipping region. But when the clipping region is set, one of the line segment is not drawn.
protected override void OnPaint(PaintEventArgs e)
{
PointF[] points = new PointF[] { new PointF(73.36f, 196),
new PointF(75.44f, 32),
new PointF(77.52f, 32),
new PointF(79.6f, 196),
new PointF(85.84f, 196) };
Rectangle b = new Rectangle(70, 32, 20, 164);
e.Graphics.SetClip(b);
e.Graphics.DrawLines(Pens.Red, points); // clipped incorrectly
e.Graphics.TranslateTransform(80, 0);
e.Graphics.ResetClip();
e.Graphics.DrawLines(Pens.Red, points);
}
Setting the antials mode on the graphics object resolves this. But that is not a real solution.
Does anybody know of a workaround?
It appears that this is a known bug...
The following code appears to function as you requested:
protected override void OnPaint(PaintEventArgs e)
{
PointF[] points = new PointF[] { new PointF(73.36f, 196),
new PointF(75.44f, 32),
new PointF(77.52f, 32),
new PointF(79.6f, 196),
new PointF(85.84f, 196) };
e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
Rectangle b = new Rectangle(70, 32, 20, 165);
e.Graphics.SetClip(b);
e.Graphics.DrawLines(Pens.Red, points); // clipped incorrectly
e.Graphics.TranslateTransform(80, 0);
e.Graphics.ResetClip();
e.Graphics.DrawLines(Pens.Red, points);
}
Note: I have AntiAlias'ed the line and extended your clipping region by 1
it appears that the following work arounds might help (although not tested):
The pen is more than one pixel thick
The line is perfectly horizontal or vertical
The clipping is against the window boundaries rather than a clip rectangle
The following is a list of articles that might / or then again might not help:
http://www.tech-archive.net/pdf/Archive/Development/microsoft.public.win32.programmer.gdi/2004-08/0350.pdf
http://www.tech-archive.net/Archive/Development/microsoft.public.win32.programmer.gdi/2004-08/0368.html
OR...
the following is also possible:
protected override void OnPaint ( PaintEventArgs e )
{
PointF[] points = new PointF[] { new PointF(73.36f, 196),
new PointF(75.44f, 32),
new PointF(77.52f, 32),
new PointF(79.6f, 196),
new PointF(85.84f, 196) };
Rectangle b = new Rectangle( 70, 32, 20, 164 );
Region reg = new Region( b );
e.Graphics.SetClip( reg, System.Drawing.Drawing2D.CombineMode.Union);
e.Graphics.DrawLines( Pens.Red, points ); // clipped incorrectly
e.Graphics.TranslateTransform( 80, 0 );
e.Graphics.ResetClip();
e.Graphics.DrawLines( Pens.Red, points );
}
This effecivly clips using a region combined/unioned (I think) with the ClientRectangle of the canvas/Control. As the region is difned from the rectangle, the results should be what is expected. This code can be proven to work by adding
e.Graphics.FillRectangle( new SolidBrush( Color.Black ), b );
after the setClip() call. This clearly shows the black rectangle only appearing in the clipped region.
This could be a valid workaround if Anti-Aliasing the line is not an option.
Hope this helps
What appears to be the matter with the code?
OK, the question should be... what should the code do that it doesn't already.
When I run the code, I see 2 red 'spikes' am I not ment to?
You appear to draw the first spike within the clipped rectangle region verified by adding the the following after the declaration of teh Rectangle :
e.Graphics.FillRectangle( new SolidBrush( Color.Black ), b );
Then you perform a translation, reset the clip so at this point I assume the clientRectangle is being used as the appropriate clip region and then attempt to redarw the translated spike. Where's the bug?!?
The bug is that both line segments should be drawn identical but they are not because the spike that is drawn within the clipping region is completely within the clipping region and should not be clipped in any way but it is. This is a very annoying but that results in any software that uses drawlines heavily + clipping to look unprofessional because of gaps that can appear in the polygons.