SoftButton Library for Adafruit 2.8" TFT LCD Touchscreen

DISCLAIMER:
This Library is NOT provided by AdaFruit and they have not
endorsed it. The use of the Adafruit name is merely to provide
a reference to which devices/libraries this library works with
and depends on. It is in no way intended to convey any affiliation
whatsoever with Adafruit or imply that Adafruit supports this
library in any way.



This library attempts to merge the push-button library functionality
(Buttons created by Franky (29/01/09)) which provides a variety of
push-button behaviors for dealing with hardware momentary switches
with the TFTLCD and TS libraries provided by Adafruit for driving
their 2.8" TFTLCD Touchscreen product.

You have to draw your own buttons.

Leave a 3 pixel margin around the edge of each button.

The 3 pixel margin is used for beveling the button to create the
effect of whether the button is pressed or not.

Note, I'm not a math major and I wanted to code to run relatively
fast, so, the beveling algorithm is pretty cheap and dirty and
doesn't do any real 3D calculations or projections.

However, the library will (assuming you call check() often enough):

  Bevel the button to reflect the current state (Pressed or not)

  Return apprpriate return codes for Press, Release, On, Off,
  and/or Repeating on a timer.

Button Modes:
  OneShot	Returns only Pressed (first time check()ed after
		being pressed) or Off (any other time)

  Memory	Returns Pressed (first time check()ed after being
		pressed), ON (still held down), Released (first
		time check()ed after being released), or OFF (still
		not pressed).

  Timer		Returns Pressed (first time check()ed after being
		pressed), ON (still down), Hold (repeat timer expired
		and still held), Released (first time check()ed)
		after being released, or OFF (still not pressed).

  OneShotTimer	Like OneShot, but will return Hold if button still
		down and repeat timer expired.

  MemoryTimer	Like Memory, but will return Hold if button still
		down and repeat timer expired.


Calling sequence:

  The instantiation of the button is rather complex. Sorry about
  that, but, I made it as simple as I could and still get full
  functionality.

  softButton B_Name(&tft, &ts, XP, XM, YP, YM, X, Y, W, H, C[, M]);

  &tft is a TFTLCD * pointer to your TFTLCD display.

  &ts is a TouchScreen * pointer to your TouchScreen

  XP, XM, YP, YM are the pins assigned for X+, X-, Y+, and Y-,
	respectively.

  X,Y are the position of the upper left corner of the button (your
	image should begin at X+3, Y+3)

  W, H are the Width and Height of the button, respectively.

  C is the Background Color of the button (a factor for the beveling
	algorithm)

  M if specified will set the operational mode of the button.
	Note: If M is not specified, the mode will default to OneShot


  Beyond instantiation, the primary thing you will use will be check():

  int state=B_Name.check();

  state can be compared to any of the button states:
  	On
  	Off
  	Pressed
  	Released
  	Hold

  When you first draw your button, it's important to call
	B_Name.bevelButton(false);

  The code is optimized to avoid unnecessary beveling calls, so your
  button might not get beveled until it gets pressed if you don't
  call bevelButton() after drawing.

  (If you call bevelButton(true), it will draw the button pressed).


Auxilialry functions:

  Just like the hard Button library, you can change the behavior
  of your softButtons.

	B_Name.setMode(byte mode);
	B_Name.setTimer(unsigned int t);
	B_Name.setRefresh(unsigned int r);

  For convenience, your button drawing routine(s) can make use of the
  following public variables:

	TFTLCD *B_Name.Display		The Display associated with
					the button

	TouchScreen *B_Name.ts		The touchscreen associated
					with the button

	unsigned int bgcolor		The background color of the
					button

	unsigned int x1, y1		Upper left corner of
					button+bevel coordinates

	unsigned int x2, y2		Lower right corner of
					button+bevel coordinates
					Note: Button Image should be
					constrained to (x1+3, y1+3) -
					(x2-3, y2-3) Otherwise, your
					image will be partially
					overwritten by beveling.



An example button drawing function:


void drawArrowButton(softButton *B, byte Direction,
                     unsigned int fgcolor)
{
  unsigned int x1, y1, width, height, bgcolor;
  x1=B->x1+3;
  y1=B->y1+3;
  bgcolor=B->bgcolor;
  width=B->x2-B->x1-6;
  height=B->y2-B->y1-6;
  // Minimum 10x10 button (+3 pixel wide bevel)
  x1 = constrain(x1, 0, 229);
  y1 = constrain(y1, 0, 309);
  width = constrain(width, 10, 239-x1);
  height = constrain(height, 10, 319-y1);
  
  B->Display->fillRect(x1, y1, width, height, bgcolor);
  x1+=2;
  y1+=2;
  width-=2;
  height-=2;
  if (Direction != constrain(Direction, 0, 3))
    Serial.println("drawArrowButton: Invalid Direction");
  Direction %= 4;
  // We use >>1 in the following statements as a fast divide-by-2
  if (Direction == 0) B->Display->fillTriangle(
    x1,y1+height, x1+(width>>1), y1,
    x1+width, y1+height, fgcolor);  // Uparrow
  if (Direction == 1) B->Display->fillTriangle(
    x1, y1, x1, y1+height,
    x1+width, y1+(height>>1), fgcolor);       // Rightarrow
  if (Direction == 2) B->Display->fillTriangle(
    x1,y1, x1+(width>>1), y1+height,
    x1+width, y1, fgcolor);         // Downarrow
  if (Direction == 3) B->Display->fillTriangle(
    x1,y1+(height>>1), x1+width, y1,
    x1+width, y1+height, fgcolor);  // LeftArrow
  B->bevelButton(false);
}

The above code isn't part of the library, but, you are welcome
to use it with the library.

It draws an arrow button within the constraints described above
taking as much data as it can from the Button object. Note that
you only pass the drawing function 3 parameters:

	The Button reference.
	The direction the Arrow should point
		(0=up, 1=right, 2=down, 3=left)
	The foreground color to draw the Arrow.

The function will use the background color from the Button as well
as the button's dimensional and positional data and Display reference.