Function Documentation

bool delayDrawingDuringDsiFlush()

Returns whether drawing waits for the previous frame to finish being sent to the display.

See also setDelayDrawingDuringDsiFlush().

void setDelayDrawingDuringDsiFlush(bool enable)

When enable is true, drawing waits for the previous frame to finish being sent to the display, trading frame rate for a tear-free screen. It is false by default and can be changed at any time.

A frame is sent to the display by hardware reading it out of SDRAM. An application that takes longer to draw a frame than the display takes to refresh is still drawing while that read runs, and the two compete for the bus, which can leave part of the screen showing the previous frame. Enabling this keeps them apart, so a frame costs the drawing plus the transfer rather than whichever of the two is longer.

Giving the glyph caches internal memory removes the same contention without costing frame rate, and is worth trying first. See STM32F769I Discovery Kit for both remedies and the measured difference between them.

See also delayDrawingDuringDsiFlush().