Canvas should be more reliable in 2024

And RIP Opera.

app/javascript/src/classes/browser_view.coffee

@@ -46,15 +46,9 @@ export default class BrowserView
     @last_preload_request_active = false
     @img_box = @container.down('.image-box')
 
-    # In Opera 10.63, the img.complete property is not reset to false after changing the
-    # src property.  Blits from images to the canvas silently fail, with nothing being
-    # blitted and no exception raised.  This causes blank canvases to be displayed, because
-    # we have no way of telling whether the image is blittable or if the blit succeeded.
-    if !Prototype.Browser.Opera
-      @canvas = create_canvas_2d()
-    if @canvas
-      @canvas.hide()
-      @img_box.appendChild @canvas
+    @canvas = document.createElement('canvas')
+    @canvas.hide()
+    @img_box.appendChild @canvas
     @zoom_level = 0
 
     # True if the post UI is visible.
@@ -493,8 +487,7 @@ export default class BrowserView
       return
     @img = document.createElement('img')
     @img.className = 'main-image'
-    if @canvas
-      @canvas.hide()
+    @canvas.hide()
     @img.show()
 
     ###
@@ -1092,8 +1085,6 @@ export default class BrowserView
     if !@img.fully_loaded
       console.debug "image incomplete; can't render to canvas"
       return false
-    if !@canvas
-      return
 
     # If the contents havn't changed, skip the blit.  This happens frequently when resizing
     # the window when not fitting the image to the screen.

app/javascript/src/classes/thumbnail_user_image.coffee

@@ -21,7 +21,7 @@ $ = jQuery
 export default class ThumbnailUserImage
   constructor: (file, onComplete) ->
     @file = file
-    @canvas = create_canvas_2d()
+    @canvas = document.createElement('canvas')
     @image = document.createElement('img')
     @onComplete = onComplete
     @url = URL.createObjectURL(@file)

app/javascript/src/legacy/common.coffee

@@ -93,10 +93,6 @@ window.InitAdvancedEditing = ->
 window.distance_squared = (x1, y1, x2, y2) ->
   (x1 - x2) ** 2 + (y1 - y2) ** 2
 
-### If 2d canvases are supported, return one.  Otherwise, return null. ###
-window.create_canvas_2d = ->
-  document.createElement('canvas')
-
 Prototype.Browser.AndroidWebKit = navigator.userAgent.indexOf('Android') != -1 and navigator.userAgent.indexOf('WebKit') != -1
 
 ### Some UI simply doesn't make sense on a touchscreen, and may need to be disabled or changed.