Created attachment 4679 [details]
Display of SDL_RenderDrawRect

Using SDL_RenderDrawRect does not produce a perfect rectangle anymore.

The bottom line seems to be out by one pixel. 

See attached screenshot.

--------------------------

//Using SDL and standard IO
#include <SDL2/SDL.h>
#include <stdio.h>

//Screen dimension constants
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;

int main( int argc, char* args[] )
{
    //The window we'll be rendering to
    SDL_Window* window = NULL;
    
    SDL_Renderer* renderer = NULL;
	
    //Initialize SDL
    if( SDL_Init( SDL_INIT_VIDEO ) < 0 )
    {
        printf( "SDL could not initialize! SDL_Error: %s\n", SDL_GetError() );
    }
    else
    {
        //Create window
        window = SDL_CreateWindow( "SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN );
        if( window == NULL )
        {
            printf( "Window could not be created! SDL_Error: %s\n", SDL_GetError() );
        }
        else
        {
	    renderer = SDL_CreateRenderer( window, -1, SDL_RENDERER_ACCELERATED );
	    if( renderer == NULL )
	    {
		printf( "Renderer could not be created! SDL Error: %s\n", SDL_GetError() );
	    }

	    SDL_Rect outlineRect = { SCREEN_WIDTH / 6, SCREEN_HEIGHT / 6, SCREEN_WIDTH * 2 / 3, SCREEN_HEIGHT * 2 / 3 };
            SDL_SetRenderDrawColor( renderer, 0x00, 0xFF, 0x00, 0xFF );        
            SDL_RenderDrawRect( renderer, &outlineRect );
	    
	    SDL_Rect outlineRect2 = { SCREEN_WIDTH / 4, SCREEN_HEIGHT / 4, SCREEN_WIDTH * 2 / 4, SCREEN_HEIGHT * 2 / 4 };
            SDL_SetRenderDrawColor( renderer, 0xFF, 0xFF, 0x00, 0xFF );        
            SDL_RenderDrawRect( renderer, &outlineRect2 );
	    
	    SDL_Rect outlineRect3 = { SCREEN_WIDTH / 3, SCREEN_HEIGHT / 3, SCREEN_WIDTH / 3, SCREEN_HEIGHT / 3 };
            SDL_SetRenderDrawColor( renderer, 0xFF, 0xFF, 0xFF, 0xFF );        
            SDL_RenderDrawRect( renderer, &outlineRect3 );
	    	    
	    SDL_RenderPresent( renderer );
		
            //Wait two seconds
            SDL_Delay( 5000 );
        }
    }	
    //Destroy window
    SDL_DestroyWindow( window );

    //Quit SDL subsystems
    SDL_Quit();

    return 0;
}