I am making a game using python and pygame. I had a problem a few days ago that I needed to give my games a functionality of being resized and maintain the aspect ratio. Also everything on the screen is resized proportionately. And luckily I got a quick solution to create two different pygame surfaces. One is the screen visible to the user and the other is to manage the blitting functionality. Actually, fake screen has everything blitted and then it itself is blitted to the main screen by using
main_screen.blit((pygame.transform.scale(fake_screen, main_screen.get_rect().size), [0, 0]).
The main problem is that now since the MOUSEBUTTONDOWN events are getting triggered on the main screen and not on fake screen, But
the clicks are getting processed according to the fake screen. This means that when I click on a button after resizing, the button appears to be their but actually its at its respective position on the fake screen. This makes all the buttons loose their functionality after the VIDEORESIZE event. Can anyone help me out with this? I hope that I was able to explain.
Easy answer: use the pygame.SCALED display flag.
It resizes the main screen for you and the mouse events too, without your program needing to know anything about it. Documented on this page: https://www.pygame.org/docs/ref/mixer.html
Using this means you wouldn’t need to use a fake screen at all, or do anything at all with scaling on your end.
DIY answer:
If you still want to control the scaling yourself, you just have to scale the mouse events along with the screen. Like scale then the opposite way you scale the fake screen.
In your case it looks like that would involve dividing the mouse event x by the ratio between fakescreen width and screen width, and same with y (with heights ofc).
I got a very easy solution to this myself. I just after getting mouse x and y coordinates, changed them to proportionately corresponding points. With a simple math. I mean, if x coordinate is 15% of main screen width, then convert it to 15% of fake screen width. This way, the fake screen will get properly scaled coordinates. The mathematical equation can be as follows:-
mouse_x = mouse_x/(xd/100)
mouse_x *= 10
mouse_y = mouse_y/(yd/100)
mouse_y *= 6
Here xd and yd are width and height of the resizable main screen respectively. And 10 and 6 are 1% of 1000 and 600 which are the width and height of the fake screen.
This solved my problem and game is now working perfectly.
Thank You.
I want to create a game in pygame but want it to have pixelated graphics, so instead of resizing a pixelated image, i was hoping to just change the resolution of the pygame screen .
screen = pygame.display.set_mode((width, height))
Thanks.
Make two screens. One with your desired resolution( let's call screen) and the other with your desired screen size(let's call window). Then blit screen into window while scaling it to the size of the window.
window.blit(pygame.transform.scale(screen,(windoWidth,windowHeight)),(0,0))
That should work.
EDIT: As the Ted's comments suggests it will be more easy to understand like this.
resized_screen = pygame.transform.scale(screen, (windoWidth,windowHeight))
window.blit(resized_screen, (0, 0))
Code:
import pygame
pygame.init()
screen = pygame.display.set_mode((400, 400))
What happens:
The pygame screen pulls up, but there is a black box covering the top right-hand corner of the screen. I would post a picture but stack overflow wouldn't let me.
Yes, so what are you trying to make happen?
pygame.display.set_mode((0, 0)) should make that box full screen. Is that your objective?
When I save an image with getcanvas().postscript(file="xxx.eps"), the shape of the turtle, the pen color, the turtle color, the drawing done by the turtle, are all saved correctly. But the color of the screen is white, no matter what it's been set as. How can I retain the color that I've set? Here's a tiny example, where I default everything except screen color:
trl = turtle.Turtle() #Request a turtle to draw with
window=turtle.Screen() #Request a screen
window.bgcolor('green') #Set its color
trl.forward(100) #Draw line
ws = trl.getscreen()
ws.getcanvas().postscript(file="cline.eps")
Someone has pointed me at question 13537483 where this question has already been posed. The conclusion seems to be that the save was deliberately set this way so as not to waste ink on colored backgrounds: this changes my problem; [posting directions seem to indicate that I should post it as a separate question, but since I'm here already]:
I am really interested in saving the screen output to disk, not in printing it. I only found the .eps option in my search, and I now see that it's not what I need. Is there a way that I can write the output to tiff or pdf or jpg or...?
I've just started learning some pygame (quite new to programming overall), and I have some very basic questions about how it works.
I haven't found a place yet that explains when I need to blit or not to include a certain surface on the screen. For example, when drawing a circle:
circle = pygame.draw.circle(screen, (0, 0, 0), (100, 100), 15, 1)
I don't need to do screen.blit(circle), but when displaying text:
text = font.render("TEXT", 1, (10, 10, 10))
textpos = text.get_rect()
textpos.centerx = screen.get_rect().centerx
screen.blit(text, textpos)
If I don't blit, the text won't appear.
To be honest, I really don't know what blitting is supposed to do, apart from "pasting" the desired surface onto the screen. I hope I have been clear enough.
The short answer
I haven't found a place yet that explains when I need to blit or not to include a certain surface on the screen.
Each operation will behave differently, and you'll need to read the documentation for the function you're working with.
The long answer
What Is Blitting?
First, you need to realize what blitting is doing. Your screen is just a collection of pixels, and blitting is doing a complete copy of one set of pixels onto another. For example, you can have a surface with an image that you loaded from the hard drive, and can display it multiple times on the screen in different positions by blitting that surface on top of the screen surface multiple times.
So, you often have code like this...
my_image = load_my_image()
screen.blit(my_image, position)
screen.blit(my_image, another_position)
In two lines of code, we copied a ton of pixels from the source surface (my_image) onto the screen by "blitting".
How do the pygame.draw.* functions blit?
Technically, the pygame.draw.* methods could have been written to do something similar. So, instead of your example...
pygame.draw.circle(screen, COLOR, POS, RADIUS, WIDTH)
...they COULD have had you do this...
circle_surface = pygame.draw.circle(COLOR, RADIUS, WIDTH)
screen.blit(circle_surface, POS)
If this were the case, you would get the same result. Internally, though, the pygame.draw.circle() method directly manipulates the surface you pass to it rather than create a new surface. This might have been chosen as the way to do things because they could have it run faster or with less memory than creating a new surface.
So which do I do?
So, to your question of "when to blit" and "when not to", basically, you need to read the documentation to see what the function actually does.
Here is the pygame.draw.circle() docs:
pygame.draw.circle():
draw a circle around a point
circle(Surface, color, pos, radius, width=0) -> Rect
Draws a circular shape on the Surface. The pos argument is the center of the circle, and radius is the size. The width argument is the thickness to draw the outer edge. If width is zero then the circle will be filled.
Note that it says that "draws a shape on the surface", so it has already done the pixel changes for you. Also, it doesn't return a surface (it returns a Rect, but that just tells you where the pixel changes were done).
Now let's look at the pygame.font.Font.render() documentation:
draw text on a new Surface
render(text, antialias, color, background=None) -> Surface
This creates a new Surface with the specified text rendered on it. Pygame provides no way to directly draw text on an existing Surface: instead you must use Font.render() to create an image (Surface) of the text, then blit this image onto another Surface.
...
As you can see, it specifically says that the text is drawn on a NEW Surface, which is created and returned to you. This surface is NOT your screen's surface (it can't be, you didn't even tell the render() function what your screen's surface is). That's a pretty good indication that you will need to actually blit this surface to the screen.
Blit means 'BL'ock 'I'mage 'T'ranfser
When you are displaying things on the screen you will, in some way, use screen because that's where you are putting it.
When you do:
pygame.draw.circle(screen, (0, 0, 0), (100, 100), 15, 1)
you are still using screen but you are just not blitting because pygame is drawing it for you.
And when you use text, pygame renders it into an image then you have to blit it.
So basically you blit images, but you can also have pygame draw them for you. But remember when you blit an image, say over a background, you need to loop it back and fourth; so that it blits the background, then the image, then the background etc...
You dont need to know much more than that, but you can read all about it here Pygame Blit
I hope this helped. Good Luck!
Imagine that you are a painter:
You have a canvas, and a brush.
Let's say that your main screen surface will be your canvas, and all the other surfaces, are "in your head" - you know how to draw them already.
When you call blit, you paint on top of the surface, covering any pixels that were overlapped. That is why you need to repaint the whole screen black so that you won't have any smudges on the painting while moving an object.
As Mark already said, you can draw a circle with a function, or first blit it to a new surface, and blit that on the screen surface.
If you have a more complicated surface - curves, text etc. you wouldn't need to have a surface for that, so you don't have to do any expensive calculations, just drawing. The setback is that your program takes up more memory, so you have to choose between those 2.