First, read the English article below.

Touch the crayon icon on the far right of the top right corner of the screen. Choose a color in the color picker. Touch the screen to draw. When you're done, touch the crayon button again. If you don't like what you drew, touch the undo button (a left-pointing, curved arrow) to the left of the crayon icon. While black and white are built into Android, iOS has a rainbow slider that does not show these colors. To access white, drag your finger from the rainbow slider to the top left corner. To get black, drag your finger from the rainbow slider to the bottom center. To make gray appear, drag your finger from the rainbow slider to the bottom left corner. To find hidden colors (like baby pink and burgundy), drag your finger from the rainbow slider around the screen. On Android only, there is also a “transparent” color. Simply press down until the full-color palette appears; select the “transparent” color there. 

Now, please write a short abstract for it in Chinese. Abstract:
在照片和视频上画画。 找到隐藏的颜色。