I have a got a colour X PixMap file, GCC compiler, a working X server on a display and a very simple task: show an XPM file in colour by a C/C++ program via the X Server running on a display.
I have googled a lot and my brain is completely broken. No information about XCreatePixmapFromData. I can't get in the xloadimage sources. But putting a 1-bit depth bitmat is successfull and I want such an easy solution for a colour pixmap.
Teh pixmap is ordinary and here it is, for example, I just wanna show that it has almost the same structure as an X BitMap file (an array of constant chars) and can be included in the C/C++ program... http://pastebin.com/b5QTrDTH
A simple code example drawing a colour pixmap would be great.
That should be easy, please help!
P. S. sorry, that's my first stackoverflow question.
The name of the function is XpmCreatePixmapFromData. It is described e.g. here along with other functions and data structures.
Basically you pass the XPM data and get back two things, a pixmap and a bitmap mask. If your pixmap is rectangular, you may ignore the mask. If not, you use it to set the mask in your GC. Then you use XCopyArea to copy from the returned pixmap to the window.
You may pass NULL as the "attributes" argument. If you don't, make sure the value mask is set correctly.
You need to link with the xpm library which you may have to download somewhere. It is not a part of X11 proper.
An example can be found here.
Related
I've been trying to code an auto clicker for a simple game online (a php coded one), but I've had trouble analyzing the colors on-screen. (English isn't my first language, sorry!) I've already done a bit of C++ in university, but only for science-oriented simple console programs. (Edit: I'm working on windows!! forgot to mention)
I've already tried the getpixel function, but since my chrome window is zoomed out at 80% to get the full game in frame, it seems I'm having some DPI related issues, but looking into this made my head dizzy.
After watching a Codebullet video, I thought a better approach to this would be to take a screenshot of the problematic area, analyze it to see if the condition is filled, then delete the screenshot. The problem is, I have no idea how I could achieve this and Google didn't help much this time :\
My code is extremely messy so I can't show it right now, but it's basically just a:
-click there
-click there after 5 seconds
-click there if this pixel is this color
-repeat
Is there an easy answer to this? I'd be really thankful if there is. Have a nice day! :)
You don't need to save the screen shot if you don't want to:
Pass the target window handle to GetDC(), t will return the the device context of the window.
Pass the device context to CreateCompatibleDC() to create a compatible DC.
Use CreateCompatibleBitmap(), passing in the DC and the size of the window. This returns a handle to a bitmap
Use SelectObject() to select the bitmap
Use BitBlt() to do a bitblock transfer of the selected pixels from the regular DC into the compatible DC using the SRCCOPY raster operation code to do a normal copy.
Create a BITMAP object. Use GetObject() and pass the handle to the bitmap you created.
Create a BITMAPINFOHEADER and define the member vars. Create an array of unsigned chars big enough to fit all the pixels from your bitmap.
Use GetDIBits() passing in the handle to the compatible bitmap, the bitmap header and a pointer to the pixel array. This loads the pixels from the bitmap into the pixel array.
Now parse all that juicy pixel data, search for the colors you're looking for and test the results against your conditionals to decide what to do next.
Don't forget to delete objects and release memory & device contexts.
I believe this is the tutorial I followed where I learned this, courtesy of MSDN: https://learn.microsoft.com/en-us/windows/desktop/gdi/capturing-an-image
I have been searching around about this problem for awhile. I am making a cross platform program and I have figured out how to load an animated cursor with the windows API and how to create a cursor during run time from raw bitmap data. However I can't find good documentation for this for X11, for my Unix/Linux build of my program. I know I need to use the XRender extension functions, XRenderCreateCursor and XRenderCreateAnimCursor from this documentation https://www.x.org/releases/X11R7.6/doc/libXrender/libXrender.txt but I do not know how to use these functions and the documentation does now show any examples.
Also the raw image data is in the ARGB format, and I want to support the Alpha channel if possible with these cursors.
Could someone show me how to use the X11 and XRender (or XCursor) Library to create a cursor, static and animated, and possibly how to do it so the cursor can be used with any X11 window.
Thanks!
PS.
I am acually editing a open source libary for cross platfrom Gui that I am using for my program, and I am trying to add this feature into the libary but I am not used to programing with X11.
When it comes to X, nothing is simple.
First, review the specification of the X render extension.
The steps for creating an animated cursor are as follows.
First, you need to create a PICTURE for each frame of the animated cursor, using CreatePicture.
Use CreateCursor to create a CURSOR from each PICTURE. CreateCursor returns a CURSOR handle.
Then, you take the list of all CURSORs for all of the frames, and then use CreateAnimCursor to create a single CURSOR representing the animated cursor.
This all comes down to creating a PICTURE for each frame. A PICTURE is created using CreatePicture from a DRAWABLE and a PICTFORMAT. DRAWABLE would be the PIXMAP with the actual bitmask for the cursor's frame, and PICTFORMAT specifies which channels in the pixmap represent the red, color, and green channels, and must be one of the enumerated PICTFORMATs returned from QueryPictformat.
For more information, see the aforementioned X render extension specification.
I'm using pixel-perfect source images and SDL2 to make a program. When set to fullscreen, I'd like it to use the native resolution (the SDL_WINDOW_FULLSCREEN_DESKTOP flag) but only between a certain minimum resolution and a reasonable maximum one, after which it will stretch from the largest legal resolution. The problem is that I can only find references to the program's own window or program size on the SDL2 documentation.
Is there any function in SDL from which I could retrieve the screen width and height at least almost directly?
Or I should do something like using SDL_WINDOW_FULLCREEN_DESKTOP and then SDL_GetWindowSize() and resizing the window again? Would this even work as expected? I'd like to fins a more elegant solution than that. It feels dirty.
In the SDL 2 wiki, you have a category named Display and Window Management. It lists everything you need to know about SDL 2's management of displays (screens) and windows.
You have multiple choices, the most generic would be using SDL_GetCurrentDisplayMode or SDL_GetDesktopDisplayMode. The difference is explained in the wiki :
There's a difference between SDL_GetDesktopDisplayMode() and SDL_GetCurrentDisplayMode() when SDL runs fullscreen and has changed the resolution. In that case SDL_GetDesktopDisplayMode() will return the previous native display mode, and not the current display mode.
After setting a SDL_DisplayMode with one of these, you can retrieve its attributes w and h.
However, there is another function that might be more appropriate and straightforward : SDL_GetDisplayBounds. If I am not mistaken, it gives you the coordinates of the display relative to the whole set of displays that can be active on the computer, and also the size of the display.
Both methods need you to know the index of the display you want to know about. I have not played that much with this part of SDL 2, but I guess you can use SDL_GetNumVideoDisplays to get the number of displays (and check if there is at least one ? - I think the SDL_Window part might not work if there is no display available anyway) and choose one. Or you could pick the first one, which has index 0.
Oh, and you can look at the exemple on the page of SDL_GetCurrentDisplayMode, they effectively retreive the size of a display.
I am currently using the 16-bit libnds (Whith devkitpro) example as a basis and am trying to display text and the png background image on the same screen (in this example it is the top sceen). I am having a similar issue as this post.
I have garbage on the top of the screen (only ifconsoleInit(...) is called), similar to the first problem in the thread. The only problem is that I am displaying the background image in a different method so the fixes they made in that thread did not apply to this.
All I am looking for is whether there is a way to fix the garbage on the top of the screen. If there is a more efficient/better way to display the image, I am willing to accept it, just I haven't found a detailed enough tutorial on how to load an image as a background without using this method. Any help would be appreciated. I will answer any further questions anyone has about what is not working.
You can find the project attached here.
Sorry for the long delay but there are a few issues with your code. The first is that in Mode 4 the only background that can be set up as a 16 bit bitmap is layer 3. http://answers.drunkencoders.com/what-graphics-modes-does-the-ds-support/
Next, the layers all share a single chunk of background memory and your garbage is coming from you overwriting part of the bitmap in video memory with the characters for the font and the map for the console background. A simple solution is to move the bitmap by settings its map base to 1. This offsets its in graphics memory by 16KB which leaves 16KB of room for your text layer (this only works because we cant display the entire 256x256 image on screen at once due the the resolution of the DS as 256x256x2bytes fills up all of memory bank A...to be more correct we should assign another memory bank to the main background...but since we cant see the bottom 70 or so lines of pixels of our image anyway its okay that they didnt quite make it into video memory).
libnds also has a macro to make finding the memory for your background a bit simpler called "bgGetGfxPtr(id)" which will get a pointer to your background gfx in video memory after you set it up so you dont have to try to calculate it via an offset from BG_GFX.
In all the changes to your code should look like this (I added a version of this to the libnds code faq at : http://answers.drunkencoders.com/wp-admin/post.php?post=289&action=edit&message=1)
int main(void) {
//Top screen pic init
videoSetMode(MODE_4_2D);
vramSetBankA(VRAM_A_MAIN_BG);
int bg = bgInit(3, BgType_Bmp16, BgSize_B16_256x256, 1,0);
decompress(drunkenlogoBitmap, bgGetGfxPtr(bg), LZ77Vram); //Displays/decompresses top image
//videoSetMode(MODE_4_2D);
consoleInit(0,0, BgType_Text4bpp, BgSize_T_256x256, 4,0, true, true);
iprintf("\x1b[1;1HThe garbage is up here ^^^^^.");
iprintf("\x1b[21;1HTesting the text function...");
while(1) {
swiWaitForVBlank();
scanKeys();
if (keysDown()&KEY_START) break;
}
return 0;
}
I have a QGraphicsView for a very wide QGraphicsScene. I need to draw the background in drawBackground() and the background is a bit complicated (long loop) although it doesn't need to be repainted constantly. I store it in a static QPixmap (I tried QImage too) inside the function drawBackground() and that pixmap is what I draw onto the painter of the view. Only when needed is the QPixmap painted on again.
If I didn't use a static pixmap, the complicated background would be generated every time I scroll sideways for example. The problem is that apparently there is a maximum width for pixmaps on Windows, on my computer it's 32770. I could store a list of pixmaps and draw them side by side but it would make the code uglier and I also don't know what the maximum width of a pixmap is for every Windows machine. Since this might be a well-known problem I was wondering if anyone has a better solution.
Thanks.
You can probably avoid the windows limit by using unaccelerated raster paint device, but 32770*1024 is 100MiB of pixmap; you probably don't want to do that even if Windows would let you.
You've already thought of the usual answer (tile it in more reasonably-sized chunks and load/generate them on demand). The other piece of the usual solution is to use something like QPixmapCache to keep the recently-used tiles so you don't regenerate them too often (only when the user scrolls a long way).
You didn't say how complex your complex background is, but you might also want to look at the Mandelbrot set example for how to do piecewise rendering of an (infinitely) large background pixmap on-demand, without blocking the UI.
This is the common use case for the tiling pattern. Basically you split the background into small images.
I'm not sure why you think "it would make the code uglier". It is certainly not a one-liner. Depending whether you have fixed size background image or not, the tiling code is usually pretty straightforward.