Web-App Overview
This is the definitive version of the Emoji Drawing Pad, an interactive digital canvas. It features an expanded emoji palette and introduces a major upgrade: a Smart Eraser. Instead of crudely wiping away pixels, the eraser intelligently targets and removes individual emojis, offering precise control over your creations. All previous features like dynamic audio, undo, and a non-destructive demo mode are fully supported.
How to Use
- Select an Emoji: Click an emoji from the palette to select your drawing tool.
- Draw: Press and drag on the canvas to draw.
- Smart Eraser (๐งผ): Click the soap icon to activate the Smart Eraser. Now, when you press and drag over the canvas, it will precisely remove only the emojis your cursor touches.
- Undo (โฉ๏ธ): Click to undo your last action, whether it was drawing or erasing.
- Clear Canvas (๐๏ธ): Wipes the entire canvas clean.
- Toggle Sound (๐/๐): Turns the audio feedback on or off.
Technical Details
- Object-Oriented Canvas Management: This version moves beyond treating the canvas as a simple pixel map. It now maintains a JavaScript array,
drawnEmojis, which acts as a "scene graph." Each object in the array stores an emoji's character, its (x, y) coordinates, and its sound profile. - Smart Eraser Logic: When the eraser is active, a "hit detection" algorithm runs on pointer events. It checks the cursor's coordinates against the bounding box of each emoji object stored in the
drawnEmojisarray. If a match is found, that object is removed from the array, and the entire canvas is re-rendered from the updated array. This enables precise, object-level erasing. - State-Based Undo System: The undo functionality has been re-engineered to work with the new object model. Instead of saving raw pixel data (
getImageData), `saveState()` now saves a full copy of thedrawnEmojisarray. This is far more memory-efficient and robust. Undoing an action simply restores the array to its previous state and triggers a full canvas redraw. - Optimized Rendering: A central
redrawAll()function is now responsible for rendering the canvas. It clears the canvas and iterates through the `drawnEmojis` array, drawing each one. This function is called after any action that changes the scene globally, such as erasing, undoing, clearing, or resizing the window. - Expanded Data Structure: The main `EMOJI_DATA` object now serves as a master list for populating the palette, while the separate `drawnEmojis` array stores instances of these emojis as they are placed on the canvas.