I think the title explains it pretty clearly. I have a PKCanvasView which is partially zoomed in, and when I select a part of the drawing with the lasso tool and then move it around with my pencil, the whole view starts shifting around following my pencil.
Tried setting isScrollEnabled to false but no dice.
Related
Other questions on SE address how to speed up nested UI control resizing, but- what if there aren't any controls?
As you drag the edge of a WPF window, even a main window with no content, black bars flicker briefly during the drag. This produces a crummy feel- one that I don't want to inflict on customers:
It does get slower and heavier with a full UI on top of it as well. This doesn't even get into how ugly it looks when resizing using the top or left edges. Windows Forms- even with the heaviest UI I've built- never looks this bad right off the bat.
What can be done to make WPF window resizing performance comparable to win forms?
(I have Windows 7 x64 and a triple monitor system on an AT Radeon HD 7470.)
You could update your graphic card and try it out again but that wont change anything. The reason is pretty simple. We all get to see this sometimes based how fast/slow our computer is. Sometimes it runs smooth because we do not have many visuals to draw. The reason is no proper background color is found in graphic card at that moment in redrawing process. Your drivers are fine, and its not just because you use Wpf. Other techniques use the same mechanism behind redrawing.
The first thing WPF will do is clear out the dirty region that is going to redraw. The purpose of dirty regions is to reduce the amount of pixels sent to the output merger stage of the GPU pipeline. Here is where we see the black color. Window itself at that point has no background color or its background color is set to transparent and so to us the GPU draws the black background. Things run async in wpf which is good so.
To fix this you could set a fix color such as "White" to the Window. Then the WPF system will clean out the dirty region but fill it automatically with white color instead of black. This usually helps.
Match the window color or the color of top most layer. Dont let GPU use black and you should do fine. Btw Wpf is faster than WinForm so dont worry.
The look is crummy indeed, especially when using the top or left border.
Which exact problem your screen shot is showing depends on how long your app is taking to render as well as a couple of background related settings that you might be able to tweak to get better resize. Plus part of the ugly resize is specific to Aero.
While I can't address the specific crazy slowness of WPF redraw, I can at least give some insight on why you see black, where that is coming from, and whether you can change to a less annoying fill-in color.
It turns out there are multiple different sources of the black and the bad resize behavior from different Windows versions that combine together. Please see this Q&A which explains what is going on and provides advice for what to do (again, not specific to making WPF faster but just seeing what you can do given the speed you have):
How to smooth ugly jitter/flicker/jumping when resizing windows, especially dragging left/top border (Win 7-10; bg, bitblt and DWM)?
I have created a usercontrol that is essentially a text editor (using Graphics.Drawstring in OnPaint).
I have set AutoScroll = true, and AutoScrollMinSize values appropriately. Everything is working how it should...
EXCEPT, i would like the control to scroll itself WHILST I am currently scrolling (i.e. click and drag the scroll bar... and whilst it is being dragged the control should be scrolling the entire time). At the moment it only scrolls when the scroll bar is released (mouse up).
I have tried implementing _Scroll and invalidating the control, but that just makes it flicker uncontrollably.
I cannot find any examples online for this, due to it being difficult to describe!
Can anyone point me in the right direction please?
Control.Invalidate() will make something flicker badly. I faced this problem drawing cross-hairs over a mouse position on a PictureBox drawing a line chart before. The trick is to use (and I cant remember which one is best to come first)
Control.Update();
Control.Refresh();
in the Scroll event. Depending on what else you are drawing in the Control and how you are drawing it this may be better for you. Also this is tested on PictureBox, Control may be another matter.
We have a Canvas control that we have set to be very large such that when a user pans or zooms around they (very rarely) see the edge of the control.
This poses a number of issues. Firstly we have to render a very large surface with a lot going on which makes things slow. It also means a user could still accidentally "fall off" the edge of the ground plane.
I have tried creating any paths using StreamGeometries to make things faster and, where I can, I have frozen assets and set various objects to IsHitTestVisible = false. These have helped matters but at the end of the day we are still drawing a massive Canvas and WPF doesnt seem to be doing anything clever given the viewport
Can anyone offer some advice?
I've spend the past three days trying to figure out the iOS-6 autorotation mess, and have not arrived at a solution.
It's relatively straight-forward to have an app where all views rotate, or where rotation is completely disabled. And (conveniently for our needs) if you use a MPMoviePlayerViewController it will autorotate even if the app has autorotation disabled.
But having conditional autorotation, where some views are allowed to rotate and others are not, is elusive. I can achieve conditional autorotation (by having the root view controller "consult" the top view controller to determine what rotation it permits), but when the rotated view is exited it leaves the prior view rotated (when previously it had not been). This is not acceptable.
Has anyone cracked this nut?
(Like I told my boss, if you want a wider view you should just put wider paper in the printer.)
Further problem: Having gotten the basic conditional rotation to work (see comments below), I find that it hoses some screens in the "right wrong" circumstances. On this non-rotatable screen I press "Intro" to go to a rotatable one.
On the rotatable screen I rotate it, then return from it with it rotated. When I get back I have this screen:
The XIB file is pretty vanilla:
The errant piece appears to be the "Image View -- img_hea..." element which for some reason gets "amplified" vertically about 4x. There is no logic moving/resizing elements in the view (other than the standard UITableView stuff), and no reference at all to the problem UIImageView.
With an NSLog placed in viewWillAppear I see that the UIImageView is dimensioned 320x44 initially but 320x160 on return from the rotated screen.
This looks like an out-and-out Apple bug.
More: If I make the problem screen rotatable and rotate it right/left (back to portrait) the image is screwed up. I'm guessing that iOS "returns" to the screen before rotating back, and that's why it gets mucked up. Interestingly, in the rotated view the UIImageView is not showing up at all, with the Y dimension coming out zero in the NSLog.
Also, now that I notice it, the label that had been superimposed over the problem image is gone altogether in both rotated and post-rotation views.
OK: Turned off "Autoresize Subviews" for the overall UIVIew, and that makes things work correctly. This is the second time I've found the "Autoresize Subviews" XIB attribute causes flaky behavior.
I have a rather basic shell of a WPF app that I am creating. When I move it using the DragMove() function the app moves properly but seems to "jerk" a lot. It seems to me that the redraw rate is very low making the application look slow and unresponsive.
Currently there is no "code" besides a call to DragMove().
The XAML consists of an outer border with rounded corners and drop shadow set to RenderingBias="Performance". There is also a small gradient on the title bar and a path. But even commenting these out of the code still makes the app appear jerky and slow whilst moving.
Note I have ran this in Release and outside the debugger too.
From experience, try removing the drop shadow and you'll see much better perfomance.
http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/99faecec-395f-4a47-92ee-620b11c39ae7