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CommandStation-EX/LCDDisplay.cpp
Neil McKechnie 3327c043a1 Move statics into LCDDisplay class, and reduce RAM.
Some state variables were static in LCDDisplay.write().  Moved to class members.  Also, types of data items like row, column & character position changed to int8_t to save a few bytes of RAM.
2021-02-19 15:32:30 +00:00

112 lines
3.6 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
#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)
{
unsigned long currentMillis = millis();
if ((!force) && (currentMillis - lastScrollTime) < LCD_SCROLL_TIME)
return NULL;
do {
if (bufferPointer == 0) {
// Find a line of data to write to the screen.
if (!done) {
if (rowFirst < 0) rowFirst = rowNext;
// Skip blank rows
while (rowBuffer[rowNext][0] == 0) {
rowNext = (rowNext + 1) % MAX_LCD_ROWS;
if (rowNext == rowFirst) {
done = true; // All lines done
break;
}
}
}
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 one
slot++;
bufferPointer = 0;
if (!done) {
rowNext = (rowNext + 1) % MAX_LCD_ROWS;
if (rowNext == rowFirst) done = true;
}
}
if (slot >= lcdRows) {
// Last slot finished, reset ready for next update.
slot = 0;
done = false;
rowFirst = -1;
lastScrollTime = currentMillis;
return NULL;
}
}
} while (force);
return NULL;
}