I have created a sample application where I want to do scrolling, but I am not able to achieve the desired output.
I have tried the following code inside paint method >>>>>
g.translate(x,y);
and passing the value for variable 'y' in keydown and keyup event.
Can anyone help me out to do this?
Easiest way (though memory intensive) is to use MutableImage, and draw it with negative y coordinates.
Mutable image is just a new Image(w,h).
Then you get its Graphics context, using myImage.getGraphics(), and draw with this Graphics object. It serves as an off-screen buffer.
Than in paint(Graphics g), you call:
g.drawImage(0,y,...);
where you loop decreasing y on each system call to paint.
(don't block paint! - each call is one frame, and you're doing frame by frame animation
do the animation loop from another thread, where you decrease y, than call repaint(), and sleep).
Have you tried with decrementing the value of Y in keyUP and calling repaint() method also do same with keyDown but now the value of Y will be decrementing and call repaint() method.
Use the g.translate(x, changingYvalue);
try this.
I think that the scrollbar should be drawn inside the paint method. And you implement the keyReleased method when clicking the arrow of the scrollbar. To implement the scrolling I would prefer call repaint(); and I will manage the paint method with boolean or some other type of private variable.
Related
I developed a small tkinter GUI to display (and export) images stored in a proprietary format. I managed to load the data into a 3D numpy uint8 array. I want to display one slice of that 3D array in a tkinter.canvas. To do so I used ImageTk.PhotoImage.
Underneath the Canvas I inserted a tk.Scrollbar. My goal is to use that scrollbar to let the user actively "scroll" though the 3D Array. Basically when the slider is moved or any of the arrows is pressed the slice corresponding to the slider position should be displayed in the canvas.
Right now I have the issue that I don't understand how to set the range of the scrollbar to my z-Dimension and then how to bind the scrollbar events to the movement or arrow actions to update the canvas.
Right now I don't have example code since this is a more conceptual problem.
Could you point me in the right direction how to solve this?
Best TMC
edit: Photo
Tkinter Gui with Canvas and Scrollbar
The solution is to use tkinter.Scale instead of tkinter.Scrollbar . As a side note, the command within:
scale = tk.Scale(yourTkFrame, from_=min, to=max, orient='horizontal', command=doSomething)
passes two values to the function doSomething.
Using the Scale allows to use the scale.get() method to retrieve the position between min and max values. Those can then be used to set the image corresponding to the selected position on the slide.
So I am making a Frogger game, but have run into a problem. For the collision detection, I am using the following to check if one Tkinter canvas object is overlapping another:
canvas.find_overlapping(*canvas.bbox(imageObj))
However, I made the background a canvas object as well:
background = self.canvas.create_image(0, 0, image = self.imageData["Background"], anchor = "nw")
So the program is detecting a collision between the player and an object 24/7. Is there any way around this? I searched SO and tried putting the background in a label, but when I packed the canvas over it the background disappeared (probably because the canvas was covering it).
I can't find a way to make the canvas transparent without making the objects on it transparent as well. I also do not want to calculate the x and y boxes of each object, as that is just cumbersome and unreliable.
If someone could suggest another way, that would be awesome.
The find_overlapping method returns a list of items. Just cycle through the list and ignore the background item.
I would like to implement red lines moving oh H/V rulers similar to what I see in windows paint brush (8.1) indicating current mouse position. See the example (red line at 560):
What would be the best way to do it. Direct2D Animation? layers? any other simple trick? The thing here is of cause doing it efficiently without repainting the whole area on mouse move.
I currently using MFC/direct2d so I paint myself the area with field and rulers inside the view, so I have full control on graphics here.
There are many ways to attack this problem. The simplest is to rely on your OnPaint function to paint the line in a location based on a member variable. In your OnMouseMove handler, call InvalidateRect on the current location of the line based on the saved variable, update the variable, and call InvalidateRect a second time for the new line position.
The BeginPaint call that is generated in the CPaintDC constructor will set a clipping region based on the invalidation rectangles you provided. Even if your OnPaint tries to paint the entire window, only those parts that have been invalidated will be redrawn. If this is too inefficient, you can cache the ruler in a bitmap and use GetClipBox to determine which part of the bitmap to blit to the screen.
I'm new to MFC. I know how to draw a line and how to scribble in MFC. I use CDC and some functions such as LineTo() and MoveTo() to do this. Moreover, I've got FillRect() and Rectangle().Now I want to drag my rectangle or any polygon in the view.It's like you drag a icon on your desktop.
I think the first step is to get the region.Then erase the old polygon and when the mouse move draw a same polygon which depends on the point where the mouse go.
So I search region in MSDN and I got Region class and CRgn class.But before I look into these two class I want to know whether I'm in the right direction.
I need more suggestions on how to learn MFC. Actually,all I need is to finish my homework which is mainly about draw polygons and drag them and link them by line. And I hope I can finish this homework all by myself and MSDN. Can MSDN help me do that?
The CDC::Polyline function will draw a polygon much faster than using LineTo and MoveTo.
You do not need region and do not need to erase the old polygon. Instead, you need to draw everything in the view OnDraw. Any change you want to make with the mouse should change the array of coordinates that represent the polygon and then call Invalidate. In other words, do not draw in the mouse message handlers. Calling Invalidate in the mouse message handlers will cause OnDraw to be called later and it should repaint the entire view.
I've been stumbling over this for a while and was wondering if anyone has run into this problem before.
The application I'm working on is divided into multiple data plots and a single timeline at the bottom of the screen. Each plot (which is actually multiple textures layered on top of each other) as well as the timeline is rendered to a separate texture. The timeline texture is rendered first, followed by each of the plot textures from the top of the screen to the bottom. I am using DXUT and DirectX9 (March 2009).
After adding time text to the timeline texture, I noticed that the text was repeated in the title bar of every data plot. Here's a screencap of a portion of the display, it shows just a single plot, but the text repeats on every plot opened:
It seems like it is tied directly to the DrawText being called in the timeline's render function. I do use relative coordinates as the rect being passed to DrawText, but since I've already set the render target to the desired texture it should only affect the current texture. Not every texture rendered afterward.
Has anyone ever run into any problems similar to this using D3DXFont?
EDIT: After some more experimentation, it looks like it has something to do with the Z buffer. By adding D3DCLEAR_ZBUFFER to the clear on each texture surface, the duplicate text is gone. While the problem seems bypassed for now, I'm still curious as to why the Z buffer for a completely separate texture was being written during my DrawText call.
The Z Buffer state is persistent.
For example,
SetDepthStencilSurface(X)
SetRenderTarget(A)
Draw()
SetRenderTarget(B)
Draw()
Both Draw calls will use the same depth buffer.
The DrawText is not changing the depth buffer that you have set. It assumes you meant to do what you did.