You can access the Colors by tapping on the Color icon at the top-right of the interface.
The icon circle contains the current color.
When you first open the Color panel, you see the chromatic wheel which allows you to easily choose your colors.
You can choose the hue with a drag around the external wheel and the saturation and brightness inside the triangle.
There is a history at the bottom of each tab of the panel. It contains the current color if you have just opened the app, otherwise it contains that color + all those which have been applied on the canvas since you opened the app.
You can choose the hue with a drag around the external wheel and the saturation and brightness inside the triangle.
There is a history at the bottom of each tab of the panel. It contains the current color if you have just opened the app, otherwise it contains that color + all those which have been applied on the canvas since you opened the app.
You can switch between a triangle or a square color wheel by tapping on the corresponding icon.
The second tab at the bottom gives you access to the sliders which allow you to choose the desired color with the values red, green, blue, hue, saturation and brightness. And under these values you can access and change the hexadecimal value.
The second tab at the bottom gives you access to the sliders which allow you to choose the desired color with the values red, green, blue, hue, saturation and brightness.
And under these values you can access and change the hexadecimal value.
The 3rd tab gives you access to the Palettes.
Double-tap on the palette name to rename it.
Tap on the circle to add the current color to the palette.
Long touch on a color to delete it.
Swipe from right to left to access more options:
Export allows you to export your palette.
Select sets the palette as main palette, and delete deletes it.
Double-tap on the palette name to rename it.
Tap on the circle to add the current color to the palette.
Long touch on a color to delete it.
Swipe from right to left to access more options:
Export allows you to export your palette.
Select sets the palette as main palette, and delete deletes it.
If you have several palettes, select one as the main palette to access it in the chromatic Wheel tab and add colors to it more quickly.
If you have several palettes, select one as the main palette to access it in the chromatic wheel tab and add colors to it more quickly.
Tap on + to create a new palette.
Tap on the Import icon to import a palette. You can also access the chromatic wheel and your palettes from the floating menu.
The color picker is located next to the color circle at the top-right of the interface. Tap on it then drag it through the interface to find and choose your color, which then becomes the current color. 
The paint bucket tool in the side-bar allows you to fill an area with the current color. The area is limited by a selection and/or by the pixels visible on all layers, if the shapes are closed.
Hold the Pencil on the screen to adjust the tolerance of the fill from 0 to 255. Slide to the left to get closer to 0, and to the right to get closer to 255.
If your line is big, contrasted and without holes, you will be able to adjust the tolerance closer to 255.
On the contrary of your line is thin, with variations of opacity (anti-aliased), and with holes, you will need to adjust the tolerance closer to 0.
