Matlab 2015 & Psychtoolbox 3： CenterRect - square而不是居中

Question

这个短程序应该显示一个绿色的全屏背景和中间有一个400 x 400像素的红色正方形。然而，红色方块位于左上角[0, 0, 400, 400]，而不是居中。

try
    screens = Screen('Screens'); % check for number of screens (currently '0' because only one screen is connected)
    whichscreen = max(screens);
    [myscreen,rect]=Screen('OpenWindow', whichscreen, [0, 255,0]);
    screen_rect = [0, 0, 1366, 768];
    square_size = [0, 0, 400, 400];
    square_rect = CenterRect(square_size, screen_rect);
    Screen('FillRect', myscreen, [255, 0, 0], square_size);
    Screen('Flip', myscreen);
    KbWait;
    Screen('CloseAll');
catch
    Screen('CloseAll');
end

而且，程序不会在按键盘上的按钮时关闭。

知道是什么问题吗?

谢谢,最好的J

Answer 1

您使用了错误的变量。你画的是一个指向square_size的矩形，而不是你想要的指向square_rect的矩形——因此很明显，这个矩形是指向[0, 0, 400, 400]的。

try
    screens = Screen('Screens'); % check for number of screens (currently '0' because only one screen is connected)
    whichscreen = max(screens); % 
    [myscreen,rect]=Screen('OpenWindow', whichscreen, [0, 255,0]);
    screen_rect = [0, 0, 1366, 768];
    square_size = [0, 0, 400, 400];
    square_rect = CenterRect(square_size, screen_rect);
    Screen('FillRect', myscreen, [255, 0, 0], square_rect);
    Screen('Flip', myscreen);
    KbWait;
    Screen('CloseAll');
catch
    Screen('CloseAll');
end

此外，您可以使用Screen('OpenWindow')提供的rect变量使其更短，并与您使用的每个监视器兼容。

try
    screens = Screen('Screens');
    whichscreen = max(screens);
    [myscreen,rect]=Screen('OpenWindow', whichscreen, [0, 255,0]);
    square_size = [0, 0, 400, 400];
    square_position = CenterRect(square_size, rect);
    Screen('FillRect', myscreen, [255, 0, 0], square_position);
    Screen('Flip', myscreen);
    KbWait;
    Screen('CloseAll');
catch
    Screen('CloseAll');
end