From 19738af3c0ee9dee0488c8041fdbac979dfbccdb Mon Sep 17 00:00:00 2001
From: Pale Moon <git-repo@palemoon.org>
Date: Wed, 28 Jun 2017 21:44:36 +0200
Subject: [PATCH] Reinstate some caching for vector images with small enough
 dimensions.

A dimension of 400 largest size x or y should cover all common caching cases for SVG icons and web app elements,
but not caching large vector rasters that would exhaust the cache.
Final solution for #757.
---
 image/src/VectorImage.cpp | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/image/src/VectorImage.cpp b/image/src/VectorImage.cpp
index 40b50ec735..8054d9e9b0 100644
--- a/image/src/VectorImage.cpp
+++ b/image/src/VectorImage.cpp
@@ -837,21 +837,21 @@ VectorImage::CreateSurfaceAndShow(const SVGDrawingParameters& aParams)
   nsRefPtr<gfxDrawable> svgDrawable =
     new gfxCallbackDrawable(cb, ThebesIntSize(aParams.size));
 
-  // We take an early exit here without using the surface cache, because for
-  // vector images this can cause bad perf issues if large sizes are scaled
-  // repeatedly (a rather common scenario) that can quickly exhaust the
-  // cache.
-  return Show(svgDrawable, aParams);
+  // We take an early exit without using the surface cache if
+  // x or y > maxDimension, because for vector images this can cause bad perf
+  // issues if large sizes are scaled repeatedly (a rather common scenario)
+  // that can quickly exhaust the cache.
+  uint32_t maxDimension = 400;
   
-// ***** Reference: Surface cache code if needed in the future ***** //
-// e.g. if we want to use the cache for specific (small) sizes
-#if 0
   bool bypassCache = bool(aParams.flags & FLAG_BYPASS_SURFACE_CACHE) ||
                      // Refuse to cache animated images:
                      // XXX(seth): We may remove this restriction in bug 922893.
                      mHaveAnimations ||
                      // The image is too big to fit in the cache:
-                     !SurfaceCache::CanHold(aParams.size);
+                     !SurfaceCache::CanHold(aParams.size) ||
+                     // Image x or y is larger than our cache cap:
+                     aParams.size.width > maxDimension ||
+                     aParams.size.height > maxDimension;
   if (bypassCache)
     return Show(svgDrawable, aParams);
 
@@ -886,8 +886,6 @@ VectorImage::CreateSurfaceAndShow(const SVGDrawingParameters& aParams)
   nsRefPtr<gfxDrawable> drawable =
     new gfxSurfaceDrawable(surface, ThebesIntSize(aParams.size));
   Show(drawable, aParams);
-#endif
-// *****           End Reference: Surface cache code           ***** //
 }