Fix detail view blender page sizing

Author: mrtcode

src/display/blender/blender.js

@@ -290,8 +290,8 @@ class Blender {
       return this.origDrawImage(...args);
     }
 
-    const pageWidth = this.ctx.canvas.width;
-    const pageHeight = this.ctx.canvas.height;
+    const pageWidth = this.pageWidth || this.ctx.canvas.width;
+    const pageHeight = this.pageHeight || this.ctx.canvas.height;
 
     const { width, height } = this.getTransformedBoundingBox(this.ctx, dx, dy, dWidth, dHeight);
     const entirePage = Math.abs(pageWidth * pageHeight - width * height) < pageWidth * pageHeight * 0.25;

src/display/canvas.js

@@ -703,6 +703,10 @@ class CanvasGraphics {
 
     if (typeof window !== 'undefined' && window.theme && !this.ctx.skipBlender) {
       this.blender = new Blender(this.ctx, window.theme);
+      this.blender.pageWidth =
+        viewport.width * Math.abs(transform ? transform[0] : 1);
+      this.blender.pageHeight =
+        viewport.height * Math.abs(transform ? transform[3] : 1);
     }
     // For pdfs that use blend modes we have to clear the canvas else certain
     // blend modes can look wrong since we'd be blending with a white