(ns humbleui-demo.humbleui-demo
  (:require [io.github.humbleui.ui :as ui])
  (:import
   [io.github.humbleui.skija Paint Shader EncodedImageFormat Image ]
   ))

(def ui
  (let [shader (Shader/makeLinearGradient
                 (float 0)
                 (float 0)
                 (float 0)
                 (float (* 400 2 1))
                 (int-array 
                   [(unchecked-int 0xFF277da1)
                    (unchecked-int 0xFFffba08)]))
        paint  (-> (Paint.) (.setShader shader))]
    
    (ui/default-theme {}
      (ui/column
        [:stretch 0.2 
         (ui/rect paint (ui/gap 0 0))]
        
        ;; where to put this?
        (-> (ui/rect paint (ui/gap 0 0))
          (ui/image-snapshot)
          (.encodeToData EncodedImageFormat/PNG)
          .getBytes)
        ))))

(comment
  ;; example code
  (-> ui/canvas .getSurface .makeImageSnapshot)
  (-> image (.encodeToData EncodedImageFormat/PNG) .getBytes)

  (ui/start-app!
    (ui/window
      {:title "HumbleUI"}
      #'ui))
  )

; Execution error (IllegalArgumentException) at humbleui-demo.humbleui-demo/fn (REPL:29).
; No matching method encodeToData found taking 1 args for class io.github.humbleui.ui.image_snapshot.ImageSnapshot

some reference: • https://github.com/JetBrains/skija/blob/8581a6c04808c0ada7863aabed9f2a9d77353b39/examples/bitmap/src/RenderToBitmap.java#L28 • https://github.com/HumbleUI/Skija/blob/master/docs/Getting%20Started.md#rendering-the-first-image • https://clojurians.slack.com/archives/C033FTUBWH5/p1664212770642909

No, it’s because ui/image-snapshot does not do what you think it does. What do you mean “save bitmap from canvas”? What’s canvas?

Is there a way to render a jpeg or png of a rectangular element (in the humbleui window, which i was referring to as “canvas” ). Preferably constrained to specified pixel dimensions, and with optional transparency in pngs. Im a fan of your typography (primitives) taste, …and I have ptsd from css! I would like to compose and composite graphics in humblui design space, but export image assets for use in other things (email, html, etc).

So one way would be to create in-memory Surface, get Canvas from it, pass that canvas to HumbleUI component’s -draw method, and then convert surface to image. See here: https://github.com/HumbleUI/Skija/blob/master/examples/bitmap/src/RenderToBitmap.java

(even though example is called RenderToBitmap, there are no Skija Bitmap used :)

If you want to “screenshot” part of your active HumbleUI window, then you need Canvas::readPixels I think. Take a look at https://github.com/HumbleUI/Skija/blob/master/examples/scenes/src/BitmapScene.java

The way I’d do it is: create a custom HumbleUI wrapper component, wrap what you want to screenshot, inside -draw call -draw on a child, then proceed with Canvas::readPixels

There’s a rect passed to -draw that represents component’s bounds in absolute coords

Use that to construct bitmap and calculate srcX/srcY