From 06dbc893dc4bfd5d4246ab8f4051ba19c54e9f5b Mon Sep 17 00:00:00 2001
From: CaptainStouf <stouf@hardware-libre.org>
Date: Sun, 22 May 2016 03:51:06 +0200
Subject: [PATCH] Added drawLine function
Signed-off-by: CaptainStouf <stouf@hardware-libre.org>
---
README.md | 4 ++++
SSD1306.cpp | 40 ++++++++++++++++++++++++++++++++++++++++
SSD1306.h | 7 +++++++
3 files changed, 51 insertions(+)
diff --git a/README.md b/README.md
index 37bb619..1bc96f4 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,7 @@ The SSD1306Demo is a very comprehensive example demonstrating the most important
## Features
* Draw pixels at given coordinates
+* Draw lines from given coordinates to given coordinates
* Draw or fill a rectangle with given dimensions
* Draw Text at given coordinates:
* Define Alignment: Left, Right and Center
@@ -89,6 +90,9 @@ void setColor(SSD1306_COLOR color);
// Draw a pixel at given position
void setPixel(int16_t x, int16_t y);
+// Draw a line from position 0 to position 1
+void drawLine(int16_t x0, int16_t y0, int16_t x1, int16_t y1);
+
// Draw the border of a rectangle at the given location
void drawRect(int16_t x, int16_t y, int16_t width, int16_t height);
diff --git a/SSD1306.cpp b/SSD1306.cpp
index 29f8459..6f29054 100644
--- a/SSD1306.cpp
+++ b/SSD1306.cpp
@@ -96,6 +96,46 @@ void SSD1306::setPixel(int16_t x, int16_t y) {
}
}
+// Bresenham's algorithm - thx wikipedia and Adafruit_GFX
+void SSD1306::drawLine(int16_t x0, int16_t y0, int16_t x1, int16_t y1) {
+ int16_t steep = abs(y1 - y0) > abs(x1 - x0);
+ if (steep) {
+ _swap_int16_t(x0, y0);
+ _swap_int16_t(x1, y1);
+ }
+
+ if (x0 > x1) {
+ _swap_int16_t(x0, x1);
+ _swap_int16_t(y0, y1);
+ }
+
+ int16_t dx, dy;
+ dx = x1 - x0;
+ dy = abs(y1 - y0);
+
+ int16_t err = dx / 2;
+ int16_t ystep;
+
+ if (y0 < y1) {
+ ystep = 1;
+ } else {
+ ystep = -1;
+ }
+
+ for (; x0<=x1; x0++) {
+ if (steep) {
+ setPixel(y0, x0);
+ } else {
+ setPixel(x0, y0);
+ }
+ err -= dy;
+ if (err < 0) {
+ y0 += ystep;
+ err += dx;
+ }
+ }
+}
+
void SSD1306::drawRect(int16_t x, int16_t y, int16_t width, int16_t height) {
drawHorizontalLine(x, y, width);
drawVerticalLine(x, y, height);
diff --git a/SSD1306.h b/SSD1306.h
index 65f0828..3b878e6 100644
--- a/SSD1306.h
+++ b/SSD1306.h
@@ -91,6 +91,10 @@
#define SETVCOMDETECT 0xDB
#define SWITCHCAPVCC 0x2
+#ifndef _swap_int16_t
+#define _swap_int16_t(a, b) { int16_t t = a; a = b; b = t; }
+#endif
+
enum SSD1306_COLOR {
BLACK = 0,
WHITE = 1,
@@ -159,6 +163,9 @@ class SSD1306 {
// Draw a pixel at given position
void setPixel(int16_t x, int16_t y);
+
+ // Draw a line from position 0 to position 1
+ void drawLine(int16_t x0, int16_t y0, int16_t x1, int16_t y1);
// Draw the border of a rectangle at the given location
void drawRect(int16_t x, int16_t y, int16_t width, int16_t height);
--
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