/usr/share/psychtoolbox-3/PsychTests/DrawTextFontSwitchSpeedTest.m is in psychtoolbox-3-common 3.0.11.20140816.dfsg1-1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 | function DrawTextFontSwitchSpeedTest
% DrawTextFontSwitchSpeedTest - Test font settings switching speed.
%
% This is a benchmark of the speed with which Screen('DrawText') et al.
% can handle switching between different font settings between text
% drawing. Specifically it tests switching between different text sizes, text
% styles and font families. It also performs non-switched drawing to establish
% a baseline.
%
% After running for a thousand repetitions for each conditon, it prints a
% summary of drawing speed and then exits.
%
% Background:
%
% In an ideal world, changing text settings should not slow down text drawing.
% In the real world, each time you change a text setting, Screen() needs to
% recompute various things, e.g., it needs to load new font data from the
% filesystem, rasterize glyphs into little images, convert them into OpenGL
% textures and upload them into the graphics card. This takes time and slows
% down text drawing after each change of settings.
%
% The Linux text renderer can cache the precomputed data for multiple different
% sets of text settings. This means that if you alternate repeatedly between a limited
% number of different text settings, e.g., drawing text strings of different font, size or
% style within one stimulus frame, then this will be only slow on the first stimulus frame.
% Linux ptb will remember the computed font data in a cache and recycle it in successive
% repetitions of those text settings. Therefore any repetition of a previously used text
% setting is "free" and fast. The number of cacheable settings is limited, as it consumes
% memory, currently to about 40 different settings. If you exceed that number, Screen
% will expunge the least used settings and be intelligent about what to recycle and what
% not. If you use non-repetitive settings then of course no caching in the world will help
% you. If no caching can be used - or at first use of a setting - subsequent text drawing will
% be about 10 - 15 times slower.
%
% On other operating systems, nothing will be cached or recycled, resulting in generally
% much slower text drawing speeds, even with constant text settings.
%
% History:
% 22-Sep-2013 mk Written.
PsychDefaultSetup(1);
screenid = max(Screen('Screens'));
w = Screen('OpenWindow', screenid);
n = 1000;
% Test size changes:
textSize = [48, 49];
Screen('TextSize', w, textSize(1));
Screen('DrawText', w, 'Hello World!', 0, 0);
for switchit = 0:1
t1 = GetSecs;
for i=1:n
if switchit
Screen('TextSize', w, textSize(mod(i,2) + 1));
else
Screen('TextSize', w, textSize(1));
end
Screen('DrawText', w, 'Hello World!', 0, 0);
end
t2 = GetSecs;
Screen('Flip', w);
if switchit
fprintf('DrawText speed for size-change: %f msecs/draw.\n', (t2 - t1) * 1000 / n);
else
fprintf('DrawText speed for constant size: %f msecs/draw.\n', (t2 - t1) * 1000 / n);
end
end
% Test style changes:
Screen('TextStyle', w, 0);
for switchit = 0:1
t1 = GetSecs;
for i=1:n
if switchit
Screen('TextStyle', w, mod(i,2));
else
Screen('TextStyle', w, 0);
end
Screen('DrawText', w, 'Hello World!', 0, 0);
end
t2 = GetSecs;
Screen('Flip', w);
if switchit
fprintf('DrawText speed for style-change: %f msecs/draw.\n', (t2 - t1) * 1000 / n);
else
fprintf('DrawText speed for constant style: %f msecs/draw.\n', (t2 - t1) * 1000 / n);
end
end
% Test font changes:
textFont = {'Courier New', 'Times'};
Screen('TextFont', w, textFont{1});
Screen('DrawText', w, 'Hello World!', 0, 0);
for switchit = 0:1
t1 = GetSecs;
for i=1:n
if switchit
Screen('TextFont', w, textFont{mod(i,2) + 1});
else
Screen('TextFont', w, textFont{1});
end
Screen('DrawText', w, 'Hello World!', 0, mod(i,2) * 100);
end
t2 = GetSecs;
Screen('Flip', w);
if switchit
fprintf('DrawText speed for font-change: %f msecs/draw.\n', (t2 - t1) * 1000 / n);
else
fprintf('DrawText speed for constant font: %f msecs/draw.\n', (t2 - t1) * 1000 / n);
end
end
sca;
end
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