draw_line not working?

[StayWithMeSenpai]

The rect above renders correctly, but the line below it doesn't.

It doesn't even warn or error, just doesn't draw.

[StayWithMeSenpai]

This issue only seems to happen when drawing on the Canvas type, not on the WindowCanvas type

[Cobrand]

Can you short self-contained example where this happens please? We can't help you unless we have more info.

WindowCanvas is an alias of Canvas, so if that doesn't work with "Canvas" this makes me think you are using a surface canvas?

[SebastienBellanger]

I had the same issue and while writing up an example I also stumbled upon what could be wrong.

TLDR; It wont work if the canvas has the underlying pixel format PixelFormatEnum::RGB24

Here is what I am trying to do in the code below:

• Load an image as a surface
• Create a new surface with the right pixel format so that it can be used with blit_scaled
• Make a canvas from the surface
• Draw to the canvas

• Make a surface from the canvas

  // Load bmp and convert to correct pixel format so that it can be blit_scaled
  let wall_surface_bmp: Surface = sdl2::image::LoadSurface::from_file("assets/52.bmp").expect("Could not load bmp");    
  let mut wall_surface = Surface::new(wall_surface_bmp.width(), wall_surface_bmp.height(), PixelFormatEnum::RGB24).expect("Could not create wall surface");
  wall_surface_bmp.blit(None, &mut wall_surface, None);
  
  let mut wall_canvas = wall_surface.into_canvas().expect("Failed to make wall surface into canvas");
  
  // This part works
  wall_canvas.set_draw_color(Color::RGB(0, 0, 255));
  wall_canvas.fill_rect(Rect::new(10, 10, 20, 20));     
  
  // None of these work
  wall_canvas.set_draw_color(Color::RGB(0, 255, 0));
  wall_canvas.draw_line(Point::new(0, 0), Point::new(32, 32));
  wall_canvas.draw_point(Point::new(5, 5));
  wall_canvas.draw_rect(Rect::new(10, 10, 20, 20));
  
  wall_surface = wall_canvas.into_surface();

I tried two things where drawing to the canvas worked as intended:

• I tried to make the canvas directly from wall_surface_bmp. This uses the pixel format SDL_PIXELFORMAT_INDEX8
• I changed the wall_surface pixel format to PixelFormatEnum::RGBA32

The error seems to happen when trying to draw to a canvas with pixel format PixelFormatEnum::RGB24

[Cobrand]

Sounds like a problem with sdl2 directly and not this binding library, can you reproduce this in C?