//FlashDisplay will trigger the LCD's display on and off
func flashDisplay(display *hd44780.HD44780, repetitions int, duration time.Duration) {
for i := 0; i < repetitions; i++ {
err := display.BacklightOn()
utils.LogErrorandExit("Failed while flashing display", err)
time.Sleep(duration / 2)
err = display.BacklightOff()
utils.LogErrorandExit("Failed while flashing display", err)
time.Sleep(duration / 2)
}
}
func displaySingleFrame(display *hd44780.HD44780, bytes []byte, duration time.Duration) {
//Display Line 0
rightBound := 16
if len(bytes) < 16 {
rightBound = len(bytes)
}
// log.Println("Line 0: " + string(bytes[0:rightBound]))
for _, char := range bytes[0:rightBound] {
err := display.WriteChar(char)
utils.LogErrorandExit("Cannot write char to LCD:", err)
}
//Display Line 1
if len(bytes) > 16 {
display.SetCursor(0, 1)
rightBound = 32
if len(bytes) < 32 {
rightBound = len(bytes)
}
// log.Println("Line 1: " + string(bytes[16:rightBound]))
for _, char := range bytes[16:rightBound] {
err := display.WriteChar(char)
utils.LogErrorandExit("Cannot write char to LCD:", err)
}
}
//Wait for the given duration
time.Sleep(duration)
}
//DisplayMessage shows the given message on the display. The message is split in pages if needed (no scrolling is used)
//In general, only strings that can be mapped onto ASCII can be displayed correctly.
func displayEvent(display *hd44780.HD44780, event *LcdEvent) {
log.Println("LCD: Displaying message: " + event.message)
err := display.Clear()
utils.LogErrorandExit("Cannot clear LCD:", err)
if event.flash == BEFORE || event.flash == BEFORE_AND_AFTER {
flashDisplay(display, event.flashRepetitions, 1*time.Second)
}
bytes := []byte(event.message)
frames := int(math.Ceil(float64(len(bytes)) / 32.0))
// log.Println("Frames: " + strconv.Itoa(frames))
frametime := int64(math.Ceil(float64(event.duration) / float64(frames)))
// log.Println("Frame time: " + strconv.Itoa(int(frametime)))
for i := 0; i < frames; i++ {
// log.Printf("Displaying frame %v\n", i)
rightBound := (i + 1) * 32
if rightBound > len(bytes) {
rightBound = len(bytes)
}
// log.Println("Frame Content: " + string(bytes[i*32:rightBound]))
displaySingleFrame(display, bytes[i*32:rightBound], time.Duration(frametime))
if i != (frames-1) || event.clearAfter {
display.Clear()
}
}
if event.flash == AFTER || event.flash == BEFORE_AND_AFTER {
flashDisplay(display, event.flashRepetitions, 1*time.Second)
}
if event.eventType == EVENT_SHUTDOWN {
log.Println("LCD: Driver shutting down...")
display.Close()
}
}