hi im using wxWidgets in c++, I have been drawing outside of paint events using wcClientDC which caused flicker. I would like help using wxBufferedDC. I literally just replaced wxClientDC with wxBufferedDC, I taut this would work but the code does not compile due to ghe construtor arguments.
my working code is :
wxClientDC dc (panel2);
replaced with:
wxBufferedDC dc (panel2);
What do I need to do inorder to use wxBufferedDC?
To fix flicker, you must avoid drawing from outside your wxEVT_PAINT handler, buffering drawing doesn't help much if you are going to redraw the window soon anyhow. So instead of replacing wxClientDC with wxBufferedDC, get rid of wxClientDC entirely and use wxAutoBufferedPaintDC instead of wxPaintDC.
Related
In order to refresh a part of the grid, i.e., when font or alignment changes, I was using the following approach:
wxRect rect1=CellToRect(TopLeft);
wxRect rect2=CellToRect(BottomRight);
wxRect r(rect1.GetTopLeft(), rect2.GetBottomRight());
RefreshRect(r);
This was refreshing only a part of the intended block and was not working correctly.
From the suggestions of intellisense I came across RefreshBlock function and it works correctly. I searched the docs and have not found any information on it. I wonder if it is not recommended to use RefreshBlock for some reason? What does RefreshBlock do, does it refresh a block (as the name suggests) or is it equivalent to Refresh?
I am using wxWidgets 3.2 on Win10.
Thanks in advance.
The function RefreshBlock() is indeed the best way to do what you want and it was only undocumented by mistake, i.e. we simply forgot to do it. I've added documentation for it only now, so it will only get included in 3.2.1, but you can still use it in your code, the function itself is available since 3.1.3.
It seems from the source code that, depending on the location of its parameters, RefreshBlock refreshes any of the following:
corner grid
frozen cols grid
frozen rows grid
main grid
Since the area I wanted to refresh was on the main grid the following approach works (the idea is similar to RefreshBlock's approach):
auto GridWnd = CellToGridWindow(TL);
wxRect rect = BlockToDeviceRect(TL, BR, GridWnd);
GetGridWindow()->RefreshRect(rect);
Now everything is refreshed correctly.
Notes:
If only RefreshRect(rect) is called, things will NOT work as expected.
Little experiment showed that BlockToDeviceRect(TL, BR) also works, therefore eliminating the need for auto GridWnd = CellToGridWindow(TL);
I would like to start off by mentioning that I am very new to coding, so some things that might seem very simple to someone with intermediate experience will probably not click quite as fast with me.
Okay so with the code I am writing, I am trying to get a three.js cube object to move to the places I click, using tweening. I managed to get this to work, but when I try to create a frame using three.js lines, the code stops working. In detail: when I add
line = new THREE.Line( lineGeometry, new THREE.LineBasicMaterial() );
scene.addObject( line );
to the Init() function. What is cause of this? My guess is it has something to do with global/local variables but even if that were correct I have no idea how to fix it !
This is the jsfiddle for reference
I'm using matplotlib housed in a wxPython panel to do some heavy duty plotting. My issues comes when using native panning tool - it's appears as though matplotlib tries to constantly redraw the canvas as you drag the pan handle around. With the amount of data I'm plotting this is getting really choppy (already optimized with Collections for data etc)
In terms of performance I think it would be much preferable for the canvas to just draw once when the mouse is released at the end of a pan. I realise this will mean I have to extend the WxAgg NavigationToolbar2 class with my own, but I'm wondering if anyone has attempted something similar to this and can advise me on which functions to override?
many thanks
I've spent a lot of time making modification on the matplotlib backends, I've never done this specific change, but I can show you one line of code to comment out that will stop the dynamic updating:
I presume you are using the WxAgg backend, if this is the case, open this file: C:\Python27\Lib\site-packages\matplotlib\backends\backend_wx.py
And comment out the line indicated here:
def dynamic_update(self):
d = self._idle
self._idle = False
if d:
#self.canvas.draw() #<--- Comment out to stop the redrawing during the Pan/Zoom
self._idle = True
I tested this and it seems to nicely solve your issue. I did some quick digging and I didn't see any other functions calling this procedure so you might even be able to just change it to:
def dynamic_update(self):
pass
...Which is the same code you'll find in the base NavigationToolbar2 class
(And of course, if you're happy with this change you can do a little more work to make your own custom backend with this kind of modification. Just to make sure you don't lose the change when upgrading matplotlib)
I am working on trying to make a splitview based application. I am trying to use Apple's MultipleDetailView example code
http://developer.apple.com/library/ios/#samplecode/MultipleDetailViews/Introduction/Intro.html
I have never really used example code like this (I usually just atart from scratch). All i did was copy the code into the correct classes of my app, but when I try to run it on the simulator the app doesn't open.
I feel like I am maybe forgetting something obvious, since I didn't code it myself.
Thanks!
The usual debugging technique applies. Put a breakpoint somewhere early in the program -- the first line of main() for instance, and debug from there. Do you hit the breakpoint? If yes, move forward through the code until you find the line that causes the problem. If no, try to back up even further if you can, and also look for any clues as to what's going wrong. If the app is running at all, there should be some sort of error message in the console output.
"...the app doesn't open" doesn't tell us nearly enough to help you. Something like "the app delegate is instantiated, but it's window and splitViewController properties are nil" goes much further toward getting to the root of the problem.
So ive been doing some iphone development with some OpenglES in it, but i am getting a rather weird error when i call prepareToDraw on my effect. My program in short simulates dice rolling (trying to learn objective-c and opengl). The program works fine for the most part, i can use everything ive programmed my app to do (with its bugs in the physics but ill fix that later). The problem comes in after ive used the part that contains the OpenGL.
The program contains 2 menu's you have to go through in order to reach the screen that is using OpenGL, once you have used the apps OpenGL part and go back to the previous menu, then try go back to the OpenGL part again, i get a print out saying GL ERROR: 0x0501. ive narrowed it down to be caused by the prepareToDraw method from my effect. The other weird part about it, is if i go back, then forward again, the OpenGL works again, and can be repeated again and again for it to be working and breaking every second time you go into the OpenGL part.
I've been searching around for similar problems to mine, but each time its got something to do with loading textures that are not a power-of-two texture, which doesnt help me because im not even using textures yet, just colored vertices.
ive pastebin'd my two code files where the problem should lie
Dice.m: http://pastebin.com/ze1DEEzs
in the draw method you'll see my printouts have narrowed down where the problem lies, which is the prepareToDraw method. (line 308)
RollViewController.m: http://pastebin.com/VycwAh3R
this file is where i setup the effect and the context etc, so i must be doing something wrong in here to cause the prepareToDraw method to mess up every 2nd time i run the OpenGL part of the program. i have a feeling it has something to do with not letting go some kind of resource to do with the context and the effect, but i cant find anything about deleting context and effect (probably because you dont need to but im not sure).
I hope there is someone out there that has run into the same problem and can answer my question and i hope its not just a silly mistake because ive been trying to solve this for a while now :)
thanks
After much pain and suffering i finally found a fix to the problem. Im not exactly sure why this is a problem, but creating the context within the OpenGL part (aka RollViewController.m) is not the way to do it. Instead you should create it once throughout the lifetime of your program and just set your current context for your glkview to be the context you have made. Maybe someone can enlighten me why recreating the context is a bad idea.
In my code i have a profile object that gets passed around between views and menu's so that they can all communicate with the same data, so i just defined a public context within my profile object so that everything can get access to the context instead of creating their own (and breaking).
The error seems general and might be because of different issues. I avoided it(for now) by not using mipmaps. I commented the following code I had and don't have the error anymore.
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
glGenerateMipmap(GL_TEXTURE_2D)