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changed fastvhline to point to drawline, added fillScreen, a fake con…
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…structor and rotation stuff
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@ladyada
ladyada committed Mar 16, 2012
1 parent 7ef9c2e commit 17a6c8b
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Showing 2 changed files with 70 additions and 18 deletions.
63 changes: 53 additions & 10 deletions Adafruit_GFX.cpp
View file
Expand Up @@ -18,6 +18,18 @@ All text above must be included in any redistribution
#include "glcdfont.c"
#include <avr/pgmspace.h>

void Adafruit_GFX::constructor(uint16_t w, uint16_t h) {
_width = WIDTH = w;
_height = HEIGHT = h;

rotation = 0;
cursor_y = cursor_x = 0;
textsize = 1;
textcolor = 0xFFFF;
textbgcolor = 0x0000;
}


// draw a circle outline
void Adafruit_GFX::drawCircle(uint16_t x0, uint16_t y0, uint16_t r,
uint16_t color) {
Expand Down Expand Up @@ -46,7 +58,6 @@ void Adafruit_GFX::drawCircle(uint16_t x0, uint16_t y0, uint16_t r,
drawPixel(x0 - x, y0 + y, color);
drawPixel(x0 + x, y0 - y, color);
drawPixel(x0 - x, y0 - y, color);

drawPixel(x0 + y, y0 + x, color);
drawPixel(x0 - y, y0 + x, color);
drawPixel(x0 + y, y0 - x, color);
Expand Down Expand Up @@ -175,7 +186,6 @@ void Adafruit_GFX::drawLine(int16_t x0, int16_t y0,
void Adafruit_GFX::drawRect(uint16_t x, uint16_t y,
uint16_t w, uint16_t h,
uint16_t color) {
Serial.println('[]');
drawFastHLine(x, y, w, color);
drawFastHLine(x, y+h-1, w, color);
drawFastVLine(x, y, h, color);
Expand All @@ -185,18 +195,14 @@ void Adafruit_GFX::drawRect(uint16_t x, uint16_t y,
void Adafruit_GFX::drawFastVLine(uint16_t x, uint16_t y,
uint16_t h, uint16_t color) {
// stupidest version - update in subclasses if desired!
for (uint16_t j=y; j<y+h; j++) {
drawPixel(x, j, color);
}
drawLine(x, y, x, y+h-1, color);
}


void Adafruit_GFX::drawFastHLine(uint16_t x, uint16_t y,
uint16_t w, uint16_t color) {
// stupidest version - update in subclasses if desired!
for (uint16_t i=x; i<x+w; i++) {
drawPixel(i, y, color);
}
drawLine(x, y, x+w-1, y, color);
}

void Adafruit_GFX::fillRect(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
Expand All @@ -207,6 +213,11 @@ void Adafruit_GFX::fillRect(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
}
}


void Adafruit_GFX::fillScreen(uint16_t color) {
fillRect(0, 0, _width, _height, color);
}

// draw a rounded rectangle!
void Adafruit_GFX::drawRoundRect(uint16_t x, uint16_t y, uint16_t w,
uint16_t h, uint16_t r, uint16_t color) {
Expand Down Expand Up @@ -403,6 +414,38 @@ void Adafruit_GFX::setTextColor(uint16_t c) {
}

void Adafruit_GFX::setTextColor(uint16_t c, uint16_t b) {
textcolor = c;
textbgcolor = b;
textcolor = c;
textbgcolor = b;
}

uint8_t Adafruit_GFX::getRotation(void) {
rotation %= 4;
return rotation;
}

void Adafruit_GFX::setRotation(uint8_t x) {
x %= 4; // cant be higher than 3
rotation = x;
switch (x) {
case 0:
case 2:
_width = WIDTH;
_height = HEIGHT;
break;
case 1:
case 3:
_width = HEIGHT;
_height = WIDTH;
break;
}
}


// return the size of the display which depends on the rotation!
uint16_t Adafruit_GFX::width(void) {
return _width;
}

uint16_t Adafruit_GFX::height(void) {
return _height;
}
25 changes: 17 additions & 8 deletions Adafruit_GFX.h
View file
Expand Up @@ -25,20 +25,26 @@ All text above must be included in any redistribution

#define swap(a, b) { int16_t t = a; a = b; b = t; }

class Adafruit_GFX : public Print{
class Adafruit_GFX : public Print {
public:

//Adafruit_GFX();
// i have no idea why we have to formally call the constructor. kinda sux
void constructor(uint16_t w, uint16_t h);

// this must be defined by the subclass
virtual void drawPixel(uint16_t x, uint16_t y, uint16_t color);

// these are 'generic' drawing functions, so we can share them!
void drawLine(int16_t x0, int16_t y0, int16_t x1, int16_t y1,
virtual void drawLine(int16_t x0, int16_t y0, int16_t x1, int16_t y1,
uint16_t color);
virtual void drawFastVLine(uint16_t x, uint16_t y, uint16_t h, uint16_t color);
virtual void drawFastHLine(uint16_t x, uint16_t y, uint16_t w, uint16_t color);
void drawRect(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
virtual void drawRect(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
uint16_t color);
void fillRect(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
virtual void fillRect(uint16_t x, uint16_t y, uint16_t w, uint16_t h,
uint16_t color);
virtual void fillScreen(uint16_t color);

void drawCircle(uint16_t x0, uint16_t y0, uint16_t r,
uint16_t color);
Expand Down Expand Up @@ -73,15 +79,18 @@ class Adafruit_GFX : public Print{
void setTextColor(uint16_t c, uint16_t bg);
void setTextSize(uint8_t s);

uint16_t height(void);
uint16_t width(void);

// return the size of the display
uint16_t width() { return WIDTH; }
uint16_t height() { return HEIGHT; }
void setRotation(uint8_t r);
uint8_t getRotation(void);

protected:
uint16_t WIDTH, HEIGHT;
uint16_t WIDTH, HEIGHT; // this is the 'raw' display w/h - never changes
uint16_t _width, _height; // dependant on rotation
uint16_t cursor_x, cursor_y, textcolor, textbgcolor;
uint8_t textsize;
uint8_t rotation;
};

#endif

3 comments on commit 17a6c8b

@svgeesus
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Why were drawFastVline and drawFastHLine made slower (and "stupider", as the comment says) by replacing the fast, straightforward loop with a call to the bresenham code which (needlessly, here) calculates the slope of the line at each step?

I assume there was some advantage to this commit but I am having a hard time seeing it. Please explain?

@ladyada
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because most screens have an optimized method for drawing straight lines that is hardware dependent, this would be overridden in the subclass.

@PaintYourDragon
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I've had a look through the code in question, ladyada's right on this one -- each subclass is intended to provide a H/V line function that's genuinely optimized to the specific hardware (the TFTLCD library shows a really good example of this). Simplifying the H/V cases to a loop of drawPixel() calls is a red herring, because that function is performing clipping on every. single. point. along. the. way...that's no optimization at all. The base class is intended to be a minimal framework -- the least code to read, maintain, debug -- just enough to test a new display device by implementing drawPixel(), hence the reduction of the H/V cases to normal line-drawing calls by default. The subclasses can then exploit hardware-specific peculiarities (memory layout, etc.) for more truly optimized graphics primitives that actually deserve the word 'fast' in their names.

"Premature optimization is the root of all evil." -- Donald Knuth

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