From d28b6f37190dc1c9cbb1e3973f8a4534b507865c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Minh=20Nguye=CC=82=CC=83n?= <mxn@1ec5.org>
Date: Fri, 6 May 2016 08:47:18 -0700
Subject: [PATCH] [ios, osx] Avoid recomputing tile cache size on every redraw

The tile cache size is only recomputed when an input changes.

Fixes #4026.
---
 platform/ios/src/MGLMapView.mm | 40 ++++++++++++++++++++++++----------
 platform/osx/src/MGLMapView.mm | 30 +++++++++++++++++--------
 2 files changed, 49 insertions(+), 21 deletions(-)

diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index eecc71ad2..8a3faa6a2 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -381,6 +381,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
     // setup mbgl map
     mbgl::DefaultFileSource *mbglFileSource = [MGLOfflineStorage sharedOfflineStorage].mbglFileSource;
     _mbglMap = new mbgl::Map(*_mbglView, *mbglFileSource, mbgl::MapMode::Continuous, mbgl::GLContextMode::Unique, mbgl::ConstrainMode::None);
+    [self validateTileCacheSize];
 
     // start paused if in IB
     if (_isTargetingInterfaceBuilder || background) {
@@ -646,15 +647,37 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 - (void)setFrame:(CGRect)frame
 {
     [super setFrame:frame];
-
-    [self setNeedsLayout];
+    if ( ! CGRectEqualToRect(frame, self.frame))
+    {
+        [self validateTileCacheSize];
+    }
 }
 
 - (void)setBounds:(CGRect)bounds
 {
     [super setBounds:bounds];
+    if ( ! CGRectEqualToRect(bounds, self.bounds))
+    {
+        [self validateTileCacheSize];
+    }
+}
 
-    [self setNeedsLayout];
+- (void)validateTileCacheSize
+{
+    if ( ! _mbglMap)
+    {
+        return;
+    }
+    
+    CGFloat zoomFactor   = self.maximumZoomLevel - self.minimumZoomLevel + 1;
+    CGFloat cpuFactor    = [NSProcessInfo processInfo].processorCount;
+    CGFloat memoryFactor = (CGFloat)[NSProcessInfo processInfo].physicalMemory / 1000 / 1000 / 1000;
+    CGFloat sizeFactor   = (CGRectGetWidth(self.bounds)  / mbgl::util::tileSize) *
+                           (CGRectGetHeight(self.bounds) / mbgl::util::tileSize);
+
+    NSUInteger cacheSize = zoomFactor * cpuFactor * memoryFactor * sizeFactor * 0.5;
+
+    _mbglMap->setSourceTileCacheSize(cacheSize);
 }
 
 + (BOOL)requiresConstraintBasedLayout
@@ -830,15 +853,6 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 {
     if ( ! self.dormant)
     {
-        CGFloat zoomFactor   = _mbglMap->getMaxZoom() - _mbglMap->getMinZoom() + 1;
-        CGFloat cpuFactor    = (CGFloat)[[NSProcessInfo processInfo] processorCount];
-        CGFloat memoryFactor = (CGFloat)[[NSProcessInfo processInfo] physicalMemory] / 1000 / 1000 / 1000;
-        CGFloat sizeFactor   = ((CGFloat)_mbglMap->getWidth()  / mbgl::util::tileSize) *
-                               ((CGFloat)_mbglMap->getHeight() / mbgl::util::tileSize);
-
-        NSUInteger cacheSize = zoomFactor * cpuFactor * memoryFactor * sizeFactor * 0.5;
-
-        _mbglMap->setSourceTileCacheSize(cacheSize);
         _mbglMap->render();
 
         [self updateUserLocationAnnotationView];
@@ -2175,6 +2189,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 - (void)setMinimumZoomLevel:(double)minimumZoomLevel
 {
     _mbglMap->setMinZoom(minimumZoomLevel);
+    [self validateTileCacheSize];
 }
 
 - (double)minimumZoomLevel
@@ -2185,6 +2200,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 - (void)setMaximumZoomLevel:(double)maximumZoomLevel
 {
     _mbglMap->setMaxZoom(maximumZoomLevel);
+    [self validateTileCacheSize];
 }
 
 - (double)maximumZoomLevel
diff --git a/platform/osx/src/MGLMapView.mm b/platform/osx/src/MGLMapView.mm
index 91410e98a..b4963535d 100644
--- a/platform/osx/src/MGLMapView.mm
+++ b/platform/osx/src/MGLMapView.mm
@@ -262,6 +262,7 @@ public:
     
     mbgl::DefaultFileSource *mbglFileSource = [MGLOfflineStorage sharedOfflineStorage].mbglFileSource;
     _mbglMap = new mbgl::Map(*_mbglView, *mbglFileSource, mbgl::MapMode::Continuous, mbgl::GLContextMode::Unique, mbgl::ConstrainMode::None);
+    [self validateTileCacheSize];
     
     // Install the OpenGL layer. Interface Builder’s synchronous drawing means
     // we can’t display a map, so don’t even bother to have a map layer.
@@ -607,6 +608,9 @@ public:
 
 - (void)setFrame:(NSRect)frame {
     super.frame = frame;
+    if (!NSEqualRects(frame, self.frame)) {
+        [self validateTileCacheSize];
+    }
     if (!_isTargetingInterfaceBuilder) {
         _mbglMap->update(mbgl::Update::Dimensions);
     }
@@ -705,15 +709,6 @@ public:
 
 - (void)renderSync {
     if (!self.dormant) {
-        CGFloat zoomFactor   = _mbglMap->getMaxZoom() - _mbglMap->getMinZoom() + 1;
-        CGFloat cpuFactor    = (CGFloat)[NSProcessInfo processInfo].processorCount;
-        CGFloat memoryFactor = (CGFloat)[NSProcessInfo processInfo].physicalMemory / 1000 / 1000 / 1000;
-        CGFloat sizeFactor   = ((CGFloat)_mbglMap->getWidth() / mbgl::util::tileSize) * ((CGFloat)_mbglMap->getHeight() / mbgl::util::tileSize);
-        
-        NSUInteger cacheSize = zoomFactor * cpuFactor * memoryFactor * sizeFactor * 0.5;
-        
-        _mbglMap->setSourceTileCacheSize(cacheSize);
-
         // Enable vertex buffer objects.
         mbgl::gl::InitializeExtensions([](const char *name) {
             static CFBundleRef framework = CFBundleGetBundleWithIdentifier(CFSTR("com.apple.opengl"));
@@ -742,6 +737,21 @@ public:
     }
 }
 
+- (void)validateTileCacheSize {
+    if (!_mbglMap) {
+        return;
+    }
+    
+    CGFloat zoomFactor   = self.maximumZoomLevel - self.minimumZoomLevel + 1;
+    CGFloat cpuFactor    = [NSProcessInfo processInfo].processorCount;
+    CGFloat memoryFactor = (CGFloat)[NSProcessInfo processInfo].physicalMemory / 1000 / 1000 / 1000;
+    CGFloat sizeFactor   = (NSWidth(self.bounds) / mbgl::util::tileSize) * (NSHeight(self.bounds) / mbgl::util::tileSize);
+    
+    NSUInteger cacheSize = zoomFactor * cpuFactor * memoryFactor * sizeFactor * 0.5;
+    
+    _mbglMap->setSourceTileCacheSize(cacheSize);
+}
+
 - (void)invalidate {
     MGLAssertIsMainThread();
     
@@ -947,11 +957,13 @@ public:
 - (void)setMinimumZoomLevel:(double)minimumZoomLevel
 {
     _mbglMap->setMinZoom(minimumZoomLevel);
+    [self validateTileCacheSize];
 }
 
 - (void)setMaximumZoomLevel:(double)maximumZoomLevel
 {
     _mbglMap->setMaxZoom(maximumZoomLevel);
+    [self validateTileCacheSize];
 }
 
 - (double)maximumZoomLevel {