I'm a newbie who wants to step the game up from Autohotkey when it comes to creating custom workflow/speed enhancing tools for windows apps that don't have plugin/API support so I'm  looking for some experienced insight into what the options, core principles / direct learning path and tools are to achieve the goal of accessing a 2D painting app's pixels and replacing  them with pixels from an external image. I assume it might have to with some reversing and memory editing/injecting so this should be a good place to ask.(edit) More concrete example as requested:Lets take Photoshop then as an accessible example (and pretend there is no plugins/API for this case). lets say we have two raster drawing layers in there, the user is painting on one, and while he is painting, i want to access the the other layer (without the user getting affected/interrupted in any way) and replace its pixel content from an external source (like a static image file to keep the example simple), kind of like just copy pasting something in there, but silently in the background, using a custom program.I assume the layer's pixel content is loaded into memory when the photoshop file is opened, and the goal is to figure out how and where those pixels are stored in the memory and gain consistent control over how photoshop deals with it and then we replace those data with our external pixels, and perhaps force a visual redraw inside the app and that should make the layer inside the app reflect the change, right?Again, im asking for the core principles/tools and what all is involved in this if its doable at all, so i know what to start learning to work my way to achieving that example and similar workflow enhancing hacks for apps that dont support plugins. (that could be making hotkeys for operations that cant be hotkeyed by default, changing sliders and settings inside the app from outside and such)Thanks for your time, if you decide to help pointing me in the right direction
Replace an app's internal pixels with data from an external image
memory;patching;hooking;graphics