I am using VB6 make a game. You move with the arrow keys, and also when you move there is a animation. I have cached the character that move's sprites into a stdPicture array, but still get flickering every time for some reason. How can I stop this? I am using an image object with transparent sprites and a solid background. I get flickering with white background on sprite and even in a picture box. Is there any way to stop the fickering? Currently I animate with LoadPicture() and I move with Image.Left = Image.Left +/- 200 etc.
You need to use double buffering which VB6 does not provide automatically. See this forum question for a VB6 solution (three quarters down the page.) In .NET you simply set a Form's double buffered property to true and it will draw flicker-free. Have you considered using VB.NET instead?
Here's another forum post with VB6 double buffer examples.
Wow! Why havent I stumbled upon this yet? I just found the solution! The solution is to use Flash. Using the Shockwave flash object removes the flickering and you can have animations. Its a double win!
Related
Capturing an image of an off-screen window with CGWindowListCreateImage is a common way to create QuickLook style zoom-in animations, but this seems create an image with the wrong background colour, slightly lighter than the real window.
This causes a flash at the end of the animation which kind of ruins the effect.
Does anyone have any idea why this happens and what can be done about it?
EDIT: I created a demonstration app for this problem. It is a bit large and complex for a Stack Overflow question, but the relevant code is probably in the ZoomingWindow.m methods takeSnapshot and makeAndPrepareSnapshotWindow.
Setting the window appearance to textured in Interface Builder fixed this. Of course that also changes the color of the window, but that is acceptable in this particular case.
We need to overlay a target window with a custom shape and tracks the position of the target window such that the overlay drawing always appears above it. Also, the overlay drawing should appear in screenshots taken using BitBlt or PrintClient by screen-capturing tools like Camtasia, Debut, etc. Also, moving the target window around should not leave traces of the drawing at earlier location. The target window is not made using our code.
So far we've tried several ways but each method has its problems:
1) Layered Window:
Using a layered window as the child/owned window of the target window is the easiest thing and it works. But the problem is on Windows 7 and XP, layered windows do not appear in a BitBlt done without the CAPTUREBLT flag and the screen-capturing tools may call BitBlt without the flag, thereby skipping our window from the capture.
2) Region Window:
The crude approach to support all Windows versions then is to use a region window using SetWindowRgn and make the target window its owner. However, region windows are generally very slow in rendering complex shapes and also impact the performance of other windows, sometimes to the point of freezing the application. Region window also leaves traces on dragging the application window.
3) Subclassing and Drawing on HDC:
Another approach is to sub-class the target window and draw the shape on its HDC on the OnPaint() event inside the window procedure hook. The shape can be drawn on the desktop window instead too. The problem is that applications may draw without a paint event, like when some text is selected using the cursor, and such drawing may erase a part of the custom drawing. Tracking all possible paint events is not a good way to do this.
4) Drawing continuously in a timer:
The last resort is to draw the custom shape on the target window in a timer continuously so the drawing is always above the target, even on text selection. But this may show a bit of flicker when the text is selected. Not to mention, it is very performance heavy to draw constantly.
Question
What is the best way to achieve an overlay drawing which works on all Windows versions (since XP) at the same time appearing in screen-captures. We've exhausted all approaches. Is there some method I'm missing? Can the above mentioned ways be used with some improvement? Is DirectX an option? I'm looking for methods with fast rendering capacity to achieve this. Appreciate any help!
I think the best solution to draw an overlay window, is to use a double-buffered technique GDI, just like in this example:
Overlay Drawing in CScrollView
I have myself the same task, and the only solution was that one. Hope it help you.
Coming from the iOS world where we have UIImageView and the property animationImages:
http://developer.apple.com/library/ios/documentation/UIKit/Reference/UIImageView_Class/Reference/Reference.html#//apple_ref/occ/instp/UIImageView/animationImages
Where animationImages is just an array of arbitrary animation frames. You specify the images (maybe 15), then set the total animation time (maybe 4 seconds) in one of the other properties, then just start the anim and the images in animationImages will play sequentially over the specified time with an even frame rate.
How would I do the same with WP7/Silverlight? This all Expression Blend seems wonderful, but I just can't find a way to animate the image source (I'm guessing it might be impossible). How would I do the same? Should I add a unique image object for each frame in the animation, then play around with visibility/opacity properties and manually have to create all the spaced out key frames? That sounds like a lot of extra work + overhead and not a nice way to go...
http://www.windowsphonegeek.com/articles/WP7-Animations-in-depthndash-Overview-and-Getting-Started
http://www.wearerighteous.com/wp7-development/xaml-animation-in-silverlight-for-windows-phone-7/
http://www.windowspresentationfoundation.com/?p=712
Try out these links. Especially the first one, I think the first one resolve all you doubts. In wp7 we can go for two options either XAML based (static) animations / or with the help of C# code. By using blend u can create all sot of static animation with out any issue. Here the animation is working on the basis of page frames. If u are interested in learning more about Animation try this too;
http://msdn.microsoft.com/en-us/library/cc189019(v=vs.95).aspx
You can actually animate the Image.Source property here's a tutorial.
Animating Images in WP7
A coworker is encountering an error when he tries to run a VB6 app we're working on. The error is, "480: Can't create AutoRedraw image". Microsoft's documentation says this is because "There isn't enough available memory for the AutoRedraw property to be set to True. Set the AutoRedraw property to False and perform your own redraw in the Paint event procedure or make the PictureBox control or Form object smaller..."
Making the PictureBox smaller isn't an option. I'd be glad to "...perform my own redraw in the Paint event procedure...", but I'm not sure how to go about it. Can someone show me the way?
Without details this will be a simplistic answer. In general most beginning VB6 programmers use AutoRedraw=True draw in responds to some input. Fill out some data, click draw, and it appears in the picture box.
The click event in the Draw Button is linked do your drawing code. The first step is move the call to the drawing code to the paint event of the picture. The second step is to replace all calls to the drawing code with MyPictureBox.Refresh. Refresh forces the paint event of that picture box to fire.
The main problem you will have to be concerned with is that the paint event is going to be fired everytime the form needs refreshed. Like if a window covering it is moved. This means that any speed issue in your drawing code will be exposed. AutoRedraw=True takes what you drew and puts in a hidden bitmap that the PictureBox uses to display what you drew.
The Paint event will execute each step of your drawing process so you have to make sure you are as fast as possible. Depending on how dynamic your application is the worse slowdown issues will become. If you are displaying a static image then the problem isn't as bad.
Making the PictureBox smaller isn't an option. I'd be glad to "...perform my own redraw in the Paint event procedure...", but I'm not sure how to go about it. Can someone show me the way?
That is easy. You just implement the _Paint()-Event of your Form or PictureBox and draw.
Because you are asking, i think i should clarify what the AutoRedraw-Propeprty does. If it is set to true, you can "just draw your image" any way you want. In multiple steps. Whatever. If it needs to be redrawn, for example, because another windows was on top it, it will be magically done. The down site is, that is slow, for the drawing part.
If AutoRedraw is false, no magic will happen. The Paint()-Event will be fired and you are responsible to draw your image again. This will be much faster, if your window is not "invalidated" (e.g. "covered") often. Or you are doing a lot of drawing.
Or you are running out of memory for the "magic space" ;-)
If you don't mind rewriting your graphics code to use the GDI API - this could be a fairly big task - I found this thread from 2006 in the VB6 discussion group, where Mike Sutton said in answer to a similar problem:
VB's back-buffer implementation uses a
Device Dependant Bitmap (DDB) to store
the image data, which is quite limited
in how large it can be made. On older
OS' this used to be ~16mb uncompressed
data size, on later OS this has been
expanded but is still quite
restrictive.
A workaround for this is to use a
Device Independent Bitmap (DIB) and
manage the GDI resources yourself,
have a look at the DIB article on my
site for an example of how to work
with them.
I haven't tried it myself.
There's usually a drop-down box of events for your control in the forms code window. You need to pick the paint event:
Private Sub object_Paint()
and fill in your your code for drawing on the PictureBox.
I'm using a VB6 PictureBox on my User Control. I set the PictureBox's picture, I set the BorderStyle to 0, and I set the BackColor to the User Control's BackColor. The idea is that I want a "floating" icon. However, I want that icon to appear clickable when the mouse hovers over it.
Two questions:
Which events do I use? MouseMove seems to be the closest to a "MouseOver" event. Are there any cleaner alternatives?
How should I change the style? I've tried a few things, but none of them quite look right.
MouseMove is the correct event in VB6. You'll have to do some work to manually detect when the mouse leaves the client area cleanly. (My experiments in this world, lo those many years ago, always found implementing this behavior to be tricky.)
For changing the style, I'd recommend using GDI to: (a) shift the image one pixel up and to the left; (b) draw a single pixel line in the ButtonHighlightColor along the top and left edges; and (c) draw a single pixel line in the ButtonShadowColor along the bottom and right edges. This is trickier than it sounds, particularly in VB6, so ultimately I'd recommend ...
That you look at vbAccelerator's toolbar controls. They're free, and they'll probably get you most of where you want to be. (And yes, they're "classic" VB -- that is, VB6.)