From 231d1ba9828c87eef92012764d260eb7fe921aa4 Mon Sep 17 00:00:00 2001
From: Daniil Manin <manindaniil@protonmail.com>
Date: Thu, 16 May 2019 18:09:50 +0700
Subject: [PATCH] #548 remove imageContextStack, add scale property to
 CGContext

---
 Source/platform/macOS/Common_macOS.swift   | 16 ++++++++++++
 Source/platform/macOS/Graphics_macOS.swift | 30 +++++++---------------
 2 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/Source/platform/macOS/Common_macOS.swift b/Source/platform/macOS/Common_macOS.swift
index c4739d2c..87a8751a 100644
--- a/Source/platform/macOS/Common_macOS.swift
+++ b/Source/platform/macOS/Common_macOS.swift
@@ -160,4 +160,20 @@ extension MBezierPath {
     }
 }
 
+extension CGContext {
+    private struct CGContextScale {
+        static var _scale: CGFloat = 0.0
+    }
+    
+    var scale: CGFloat {
+        get {
+            return CGContextScale._scale
+        }
+        
+        set(newValue) {
+            CGContextScale._scale = newValue
+        }
+    }
+}
+
 #endif
diff --git a/Source/platform/macOS/Graphics_macOS.swift b/Source/platform/macOS/Graphics_macOS.swift
index 5f93e801..57fa0fe0 100644
--- a/Source/platform/macOS/Graphics_macOS.swift
+++ b/Source/platform/macOS/Graphics_macOS.swift
@@ -11,8 +11,6 @@ import Foundation
 #if os(OSX)
 import AppKit
 
-private var imageContextStack: [CGFloat] = []
-
 func MGraphicsGetCurrentContext() -> CGContext? {
     return NSGraphicsContext.current?.cgContext
 }
@@ -54,8 +52,6 @@ func MGraphicsBeginImageContextWithOptions(_ size: CGSize, _ opaque: Bool, _ sca
     let height = Int(size.height * scale)
 
     if width > 0 && height > 0 {
-        imageContextStack.append(scale)
-
         let colorSpace = CGColorSpaceCreateDeviceRGB()
 
         guard let ctx = CGContext(data: nil, width: width, height: height, bitsPerComponent: 8, bytesPerRow: 4 * width, space: colorSpace, bitmapInfo: (opaque ?  CGImageAlphaInfo.noneSkipFirst.rawValue : CGImageAlphaInfo.premultipliedFirst.rawValue)) else {
@@ -64,32 +60,24 @@ func MGraphicsBeginImageContextWithOptions(_ size: CGSize, _ opaque: Bool, _ sca
 
         ctx.concatenate(CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: CGFloat(height)))
         ctx.scaleBy(x: scale, y: scale)
+        ctx.scale = scale
         MGraphicsPushContext(ctx)
     }
 }
 
 func MGraphicsGetImageFromCurrentImageContext() -> MImage? {
-    if !imageContextStack.isEmpty {
-        guard let ctx = MGraphicsGetCurrentContext() else {
-            return nil
-        }
-
-        let scale = imageContextStack.last!
-        if let theCGImage = ctx.makeImage() {
-            let size = CGSize(width: CGFloat(ctx.width) / scale, height: CGFloat(ctx.height) / scale)
-            let image = NSImage(cgImage: theCGImage, size: size)
-            return image
-        }
+    guard let ctx = MGraphicsGetCurrentContext(),
+        let theCGImage = ctx.makeImage() else {
+        return nil
     }
-
-    return nil
+    let scale = ctx.scale
+    let size = CGSize(width: CGFloat(ctx.width) / scale, height: CGFloat(ctx.height) / scale)
+    let image = NSImage(cgImage: theCGImage, size: size)
+    return image
 }
 
 func MGraphicsEndImageContext() {
-    if imageContextStack.last != nil {
-        imageContextStack.removeLast()
-        MGraphicsPopContext()
-    }
+    MGraphicsPopContext()
 }
 
 func MNoIntrinsicMetric() -> CGFloat {