Fix image scaling issue when rendering svg onto webview

Sources/SVGConverterCore/Internal/PixelScaleWindow.swift

@@ -0,0 +1,12 @@
+//
+//  PixelScaleWindow.swift
+//
+//
+//  Created by Alexandre Podlewski on 09/04/2022.
+//
+
+import AppKit
+
+class PixelScaleWindow: NSWindow {
+    override var backingScaleFactor: CGFloat { return 1 }
+}

Sources/SVGConverterCore/Internal/WebViewSVGRenderer.swift

@@ -79,12 +79,8 @@ final class WebViewSVGRenderer: WKWebView, WKNavigationDelegate {
         }
         isRendering = true
         self.completion = completion
-        let webViewScale = layer?.contentsScale ?? 1
         self.inPixelSize = size
-        self.inPointSize = NSSize(
-            width: size.width / webViewScale,
-            height: size.height / webViewScale
-        )
+        self.inPointSize = self.convertFromBacking(size)
         do {
             let resizedSVGData = try resizeSVG(svgData, to: self.inPointSize)
             guard let svgString = String(data: resizedSVGData, encoding: .utf8) else {
@@ -119,8 +115,6 @@ final class WebViewSVGRenderer: WKWebView, WKNavigationDelegate {
             )
         )
 
-        webView.layer?.contentsScale = 1.0
-        webView.layer?.rasterizationScale = 0.1
         webView.frame.size = config.rect.size
         webView.takeSnapshot(with: config) { [weak self] image, error in
             guard let self = self else { return }

Sources/SVGConverterCore/SVGRenderer.swift

@@ -6,6 +6,7 @@
 //
 
 import Foundation
+import AppKit
 
 @available(macOS 10.15, *)
 @MainActor
@@ -51,6 +52,7 @@ public final class SVGRenderer {
 
     // MARK: - Private Properties
 
+    private let rendererWindow: NSWindow
     private let renderer: WebViewSVGRenderer
 
     // MARK: - Life cycle
@@ -70,6 +72,14 @@ public final class SVGRenderer {
         }
         self.renderer = WebViewSVGRenderer(options: options)
 
+        // ???: (Alexandre Podlewski) 09/04/2022 Without forcing the backing scale factor it is not possible to control
+        //      the output of screeshoting the web view. Without window issues could also occurred when changing of
+        //      focused screen with a different scale factor. An issue occurred when focused on a x1 screen, with
+        //      the webview outside of a window it had a default backing scale factor of x2 but the snapshot was taken
+        //      as x1, this causing invalid size generated images.
+        self.rendererWindow = PixelScaleWindow()
+        self.rendererWindow.contentView = self.renderer
+
         self.warningHandler = warningHandler
         self.renderer.warningHandler = warningHandler
     }