From ce10f8b8c42ab67a1bf523a31e72cdcf13a98900 Mon Sep 17 00:00:00 2001 From: Roeland Jago Douma Date: Wed, 31 Oct 2018 13:40:41 +0100 Subject: Only generate previews in powers of 4 and set min Before we'd round up all preview request to their nearest power of two. This resulted still in a lot of possible images. Generating a lot of server load and taking up a lot of space. This moves it to previews to be powers of 4: 64, 256, 1024 and 4096 Also the first two powers are always skipped (4, 16) as it doesn't make sense to generate previews for that. We cache preview pretty agressively and I feel this is a better tradeoff. Signed-off-by: Roeland Jago Douma --- lib/private/Preview/Generator.php | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'lib/private/Preview') diff --git a/lib/private/Preview/Generator.php b/lib/private/Preview/Generator.php index 86579e3480b..1f7decf2b79 100644 --- a/lib/private/Preview/Generator.php +++ b/lib/private/Preview/Generator.php @@ -298,19 +298,23 @@ class Generator { if ($height !== $maxHeight && $width !== $maxWidth) { /* - * Scale to the nearest power of two + * Scale to the nearest power of four */ - $pow2height = 2 ** ceil(log($height) / log(2)); - $pow2width = 2 ** ceil(log($width) / log(2)); + $pow4height = 4 ** ceil(log($height) / log(4)); + $pow4width = 4 ** ceil(log($width) / log(4)); - $ratioH = $height / $pow2height; - $ratioW = $width / $pow2width; + // Minimum size is 64 + $pow4height = max($pow4height, 64); + $pow4width = max($pow4width, 64); + + $ratioH = $height / $pow4height; + $ratioW = $width / $pow4width; if ($ratioH < $ratioW) { - $width = $pow2width; + $width = $pow4width; $height /= $ratioW; } else { - $height = $pow2height; + $height = $pow4height; $width /= $ratioH; } } -- cgit v1.2.3