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CommandStation-EX/LCDDisplay.cpp
Neil McKechnie 38be1d6152
Refactor OLED and LCD drivers (#178)
* Refactor SSD and LCD drivers

Rework display drivers to use inheritance and to remove unused functionality.  The changes here were previously in neil-hal branch but have been separated out because of the amount of changes in neil-hal.

* Update version.h
2021-07-13 21:15:38 +01:00

164 lines
4.8 KiB
C++

/*
* © 2021, Chris Harlow, Neil McKechnie. All rights reserved.
*
* This file is part of CommandStation-EX
*
* This is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* It is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with CommandStation. If not, see <https://www.gnu.org/licenses/>.
*/
// CAUTION: the device dependent parts of this class are created in the .ini
// using LCD_Implementation.h
/* The strategy for drawing the screen is as follows.
* 1) There are up to eight rows of text to be displayed.
* 2) Blank rows of text are ignored.
* 3) If there are more non-blank rows than screen lines,
* then all of the rows are displayed, with the rest of the
* screen being blank.
* 4) If there are fewer non-blank rows than screen lines,
* then a scrolling strategy is adopted so that, on each screen
* refresh, a different subset of the rows is presented.
* 5) On each entry into loop2(), a single operation is sent to the
* screen; this may be a position command or a character for
* display. This spreads the onerous work of updating the screen
* and ensures that other loop() functions in the application are
* not held up significantly. The exception to this is when
* the loop2() function is called with force=true, where
* a screen update is executed to completion. This is normally
* only done during start-up.
* The scroll mode is selected by defining SCROLLMODE as 0, 1 or 2
* in the config.h.
* #define SCROLLMODE 0 is scroll continuous (fill screen if poss),
* #define SCROLLMODE 1 is by page (alternate between pages),
* #define SCROLLMODE 2 is by row (move up 1 row at a time).
*/
#include "LCDDisplay.h"
void LCDDisplay::clear() {
clearNative();
for (byte row = 0; row < MAX_LCD_ROWS; row++) rowBuffer[row][0] = '\0';
topRow = -1; // loop2 will fill from row 0
}
void LCDDisplay::setRow(byte line) {
hotRow = line;
hotCol = 0;
}
size_t LCDDisplay::write(uint8_t b) {
if (hotRow >= MAX_LCD_ROWS || hotCol >= MAX_LCD_COLS) return -1;
rowBuffer[hotRow][hotCol] = b;
hotCol++;
rowBuffer[hotRow][hotCol] = 0;
return 1;
}
void LCDDisplay::loop() {
if (!lcdDisplay) return;
lcdDisplay->loop2(false);
}
LCDDisplay *LCDDisplay::loop2(bool force) {
if (!lcdDisplay) return NULL;
unsigned long currentMillis = millis();
if (!force) {
// See if we're in the time between updates
if ((currentMillis - lastScrollTime) < LCD_SCROLL_TIME)
return NULL;
} else {
// force full screen update from the beginning.
rowFirst = -1;
rowNext = 0;
bufferPointer = 0;
done = false;
slot = 0;
}
do {
if (bufferPointer == 0) {
// Find a line of data to write to the screen.
if (rowFirst < 0) rowFirst = rowNext;
skipBlankRows();
if (!done) {
// Non-blank line found, so copy it.
for (uint8_t i = 0; i < sizeof(buffer); i++)
buffer[i] = rowBuffer[rowNext][i];
} else
buffer[0] = '\0'; // Empty line
setRowNative(slot); // Set position for display
charIndex = 0;
bufferPointer = &buffer[0];
} else {
// Write next character, or a space to erase current position.
char ch = *bufferPointer;
if (ch) {
writeNative(ch);
bufferPointer++;
} else
writeNative(' ');
if (++charIndex >= MAX_LCD_COLS) {
// Screen slot completed, move to next slot on screen
slot++;
bufferPointer = 0;
if (!done) {
moveToNextRow();
skipBlankRows();
}
}
if (slot >= lcdRows) {
// Last slot finished, reset ready for next screen update.
#if SCROLLMODE==2
if (!done) {
// On next refresh, restart one row on from previous start.
rowNext = rowFirst;
moveToNextRow();
skipBlankRows();
}
#endif
done = false;
slot = 0;
rowFirst = -1;
lastScrollTime = currentMillis;
return NULL;
}
}
} while (force);
return NULL;
}
void LCDDisplay::moveToNextRow() {
rowNext = (rowNext + 1) % MAX_LCD_ROWS;
#if SCROLLMODE == 1
// Finished if we've looped back to row 0
if (rowNext == 0) done = true;
#else
// Finished if we're back to the first one shown
if (rowNext == rowFirst) done = true;
#endif
}
void LCDDisplay::skipBlankRows() {
while (!done && rowBuffer[rowNext][0] == 0)
moveToNextRow();
}