In order to achieve this goal I'm constantly learning and evolving techniques (sometimes via mashing together code) and experimenting to understand what really works best.
Digital Doodler
Artists/General Public
Digital Doodler is a mobile (phone/tablet) drawing app with features similar to those found on desktop drawing/painting programs such as Photoshop®. (Digital Doodler is not in any way associated with or endorsed by Adobe® or associated software or services; some inspiration has been drawn from Photoshop® and the PSD format is used for saving data)Features:
Color chooser with hue and saturation/brightness selectors
Brush with adjustable hardness, opacity, size, pressure sensitive, live portrait mirroring and/or landscape mirroring.
Layers with ability to add, remove, duplicate, merge, change opacity, and toggle visibility. Pinch to scale or use one finger to pan with the layer tool selected.
Camera access to images downloaded or captured with your device for import.
Sharing able to pass along the image created to any application that accepts an image (for easy e-mailing/texting/storing of images on cloud services).
Save for storage on the local device as a PNG.
Undo/Redo for drawing
Please feel free to e-mail me directly about any issues you encounter or suggestions you have for the application.
Instructions
Here's a quick rundown of what each of the icons in the application represents:
| Tool Name | Description |
|---|---|
| Open/Close Menu | Hides or shows the panel containing the remaining buttons (always remains visible) |
| Color Chooser |
 Allows for color selection using a two step process. Initially the hue can be selected in the hue bar. This will update the saturation/lightness gradient for that hue which appears below the hue selection bar. Touching inside the saturation/lightness gradient selects the color underneath your finger (RGB color without alpha is selected). |
| Brush |
 Touching the brush once selects the brush tool, touching it a second time opens the brush options dialog. Within the options you can change the brush width, opacity, hardness, and toggle options for pressure sensitivity, horizontal mirroring and vertical mirroring. To turn up a value using the slider touch in the green, to go down touch red, the further from the center bar the faster the value changes. When a toggle is yellow it's turned on, when grey it's turned off. When touching within the drawing region the brush draws on the current layer with the currently selected color. |
| Eraser | Follows the same exact pattern as the brush, except used to erase. Select the tool with one touch then use your finger to erase. In more technical terms this sets the alpha to the pixels in the currently selected layer to 0 wherever you touch (making them transparent). |
| Bucket | Select the bucket tool by touching it once (there are no secondary options currently). The bucket tool does a simple fill using the currently selected color on whatever color is chosen. Note the bucket currently requires that all pixels are 100% the same color for a fill to occur. |
| Navigation | Select by touching once, after selected a second tap will reset the view to the default position and zoom. With the tool selected use two fingers to zoom the view (pinch) and one finger to move the view around (note this doesn't modify your final image just the current view, good for zooming in to do details). |
| Pipette | Select the pipette tool then touch anywhere on the canvas to pick up the color. In technical terms this flattens all layers into an image and picks up the RGB color underneath the finger in the flattened image. |
| Undo | Can Undo up to 10 steps. Clears the current layer and draws the previously saved data in the undo stack. |
| Redo | Can redo as many steps as have been undone. Data ahead of the current image is cleared when a new action is taken. |
| Clear Layer | Clears the currently selected layer. Sets all pixels in the layer to transparent. |
| Layers |
 When tool is selected, one finger motions on the canvas will move the layer. Two finger pinch and twist motions allow you to scale and rotate a layer. After the layer tool is selected hitting it a second time brings up the extra layer options shown above. All button actions pertain to the currently selected layer (chosen in the preview list on the right of the dialog). |
| Camera | Jumps to the native camera application on your device. Once a picture is taken it's added as a new layer. |
| Import Images | Opens the device gallery to choose an image to import. Imported images are added as new layer. |
| Share | Use to share via text, e-mail, etc. Flattens the layers into a high quality PNG then passes the image to any application that can handle the intent to take an image. |
| Save | Opens a dialog to choose to save to SD card directly or save to your gallery. When saving to SD card the layers are flattened into a PNG and a dialog is presented to choose the file location. When saving to the gallery the save will happen immediately after hitting the save button. |
Developers
Note for the techies: no hard set limits though limited memory means the app will crash with Z number of layers for a phone with X memory and Y resolution, crashing will happen roughly when X>(Z*Y).For example on a Galaxy Nexus with res of 1280x720x32bpp = 3.68MB per screen, device RAM is 1GB, theoretical maximum of 271 layers (actually tested with 40 layers without a crash).
If you're a developer and would like to contribute this is an "open source" project and can be found at:
GitHub
Feel free to fork the code or send in pull requests, the code is AS3 using AIR for deployment.
Completely free forever and no ads.