Watch faces have two different display states: active and always-on. An active watch face appears when users lifts their wrists, as if looking at the watch, and when the Wake-up gesture is activated in watch settings. An always-on, or ambient, watch face always appears on the screen; it never fades away or becomes dormant when the always-on display state is activated in watch settings. These two states consume different amounts of battery power, so what the watch can display in each state is different. Make sure to consider the capabilities and limitations of each state in your design.
Active watch faces can freely express concepts and moods using diverse colors. You can extend watch functionality and usefulness using complications.
The always-on state is set to low-power mode, and color representation is restricted. Samsung recommends that you create a design that uses no more than 15% of available pixels in always-on states.
Depending on the capability of the watch’s display, two different color schemes are available for always-on states: low-bit color and high color.
Low-bit color mode
In low-bit color mode, always-on states use only cyan, magenta, yellow, red, green, blue, and white at full brightness. Grayscales and gradients cannot be used. Images might be pixelated, as low-bit color mode does not support anti-aliasing.
High color mode
The high-color mode has no color limitations, so the corresponding active versions of your watch face can be replicated more closely. However, high-color designs are displayed in low-bit color if a device does not support high color. High-color mode is supported on Gear S3 or newer devices.
Because always-on states consume power at a low rate, the on-pixel ratio (OPR) is limited to a maximum of 15%. OPR is the ratio of the sum of each on-pixel’s RGB values compared to the value when all pixels on the screen are white. The OPR increases when more pixels are on and when the sum of RGB values is higher.
OPR represents the percentage of each pixel’s RGB values. For example, a white pixel has the RGB value of R (255), G (255), and B (255) and an OPR of 100%. A red pixel’s RGB value is R (255), G (0), and B (0) and an OPR of 33.3%. A black pixel has the RGB value of R (0), G (0), and B (0), with an OPR of 0%.
Do not simply lower the brightness level of an active state to create an always-on state. This could degrade the visibility and quality of your work.
You can check the OPR value with always-on states when Settings -> Developer options -> On Pixel Ratio is on. The Developer options screen is hidden by default. To make it visible, open the watch's Settings menu, select About watch and click the Software version five times.
When the watch uses an always-on state, the watch face regularly moves around the screen by just a few pixels to prevent a burn-in from occurring on the OLED display. Be aware that design elements near the edge of a watch face can be pushed out of the display when this happens. Replace bright colors with black for the background, and avoid applying high brightness and high chroma to a large block of pixels. For an analog watch face, leave the center empty or dark.
Always-on state default screens
The watch provides different default screens for always-on states, according to the watch face type and color mode. If a watch face does not have a corresponding always-on state, the system provides a default one.