The small bit of code below blits and image to the screen within a class. I call this 4 times to display the image 4 times, each image has a different y coordinate and doesn't need different x but when they are blitted they make the code MUCH slower. I know it is the blitting as well due to the fact that if i just draw rects instead, the program moves smoothly.

tableTex = pygame.transform.scale(pygame.image.load('./Sources/Table.png'), (270, 240))

    def display(self):
        if not self.occupied:
            screen.blit(tableTex, (self.x, self.y))
            pygame.draw.rect(screen, (127, 0, 0), self.rect, 0)

A link to the full code can be found here if needed. I just want to know if there is any reason this is so slow and if there are any other methods I could use that are faster?


  • \$\begingroup\$ You should add the definition of tableTex to the code, since it is actually quite relevant. \$\endgroup\$ – Graipher Jul 3 '18 at 15:49
  • 1
    \$\begingroup\$ @Graipher My bad - Updated it now \$\endgroup\$ – Thomas Ayling Jul 3 '18 at 15:51

As noted in the beginners guide, you should convert your image right after loading it. So instead of

tableTex = pygame.transform.scale(pygame.image.load('./Sources/Table.png'), (270, 240))


tableTex = pygame.transform.scale(pygame.image.load('./Sources/Table.png').convert(), (270, 240))

As noted in the guide linked above, this can lead to a speed-up of about a factor 6. The reason is:

The 'format' that convert() refers to isn't the file format (ie PNG, JPEG, GIF), it's what's called the 'pixel format'. This refers to the particular way that a surface records individual colors in a specific pixel. If the surface format isn't the same as the display format, SDL [what pygame uses underneath] will have to convert it on-the-fly for every blit -- a fairly time-consuming process. Don't worry too much about the explanation; just note that convert() is necessary if you want to get any kind of speed out of your blits.

  • \$\begingroup\$ Thanks very much for the reply, however using convert adds some very strange deformities to my loaded images imgur.com/a/htautZi \$\endgroup\$ – Thomas Ayling Jul 3 '18 at 15:55
  • \$\begingroup\$ @ThomasAyling: I don't see them. But I just changed my answer to call convert on the loaded image, not the scaled one. Does that change anything? \$\endgroup\$ – Graipher Jul 3 '18 at 15:57
  • \$\begingroup\$ No, i still get the same problem imgur.com/a/80IPaj7 (New image) \$\endgroup\$ – Thomas Ayling Jul 3 '18 at 15:59
  • \$\begingroup\$ @ThomasAyling: That does indeed look weird (comparing it to the original in the github). Maybe the picture contains transparency which is wrongly interpreted? \$\endgroup\$ – Graipher Jul 3 '18 at 16:01
  • \$\begingroup\$ Possibly, it works properly without the convert in still so maybe there were some issues with compression, i'll try re-saving it from Photoshop \$\endgroup\$ – Thomas Ayling Jul 3 '18 at 16:03

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