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draw_handler (short: ld)

The handler receives self as its implicit parameter (object-oriented style). This handler is part of the LCD element and is triggered repeatedly to update the screen display.

Available Methods via self

LCD-specific parameters

Short Human Name Description
ind element_index Element index
lin screen_index Screen index used by low-level APIs
lsw screen_width Screen width in pixels
lsh screen_height Screen height in pixels

Drawing functions

Short Human Name Usage
ldsw draw_swap self:ldsw() - Updates screen with background buffer
ldpx draw_pixel self:ldpx(x, y, {r, g, b}) - Draw pixel
ldl draw_line self:ldl(x1, y1, x2, y2, {r, g, b}) - Draw line
ldr draw_rectangle self:ldr(x1, y1, x2, y2, {r, g, b}) - Draw rectangle
ldrf draw_rectangle_filled self:ldrf(x1, y1, x2, y2, {r, g, b}) - Draw filled rectangle
ldrr draw_rectangle_rounded self:ldrr(x1, y1, x2, y2, radius, {r, g, b}) - Draw rounded rectangle
ldrrf draw_rectangle_rounded_filled self:ldrrf(x1, y1, x2, y2, radius, {r, g, b}) - Draw filled rounded rectangle
ldpo draw_polygon self:ldpo({x1, x2, ...}, {y1, y2, ...}, {r, g, b}) - Draw polygon
ldpof draw_polygon_filled self:ldpof({x1, x2, ...}, {y1, y2, ...}, {r, g, b}) - Draw filled polygon
ldt draw_text self:ldt('text', x, y, size, {r, g, b}) - Draw text
ldft draw_text_fast self:ldft('text', x, y, size, {r, g, b}) - Draw text (fast)
ldaf draw_area_filled self:ldaf(x1, y1, x2, y2, {r, g, b}) - Fill area (no alpha)
ldd draw_demo self:ldd(n) - Draw n-th demo iteration

General functions

Short Human Name Description
gen element_name Get element name
gsen element_name_set Set element name
glsb lcd_set_backlight Set LCD backlight level

Default Action String

The default draw handler implements a value display with rounded rectangles:

if self.f>0 then
  self.f=self.f-1
  local a,xo=gmaps(self.v[1],self.v[2],self.v[3],0.1,1),#tostring(self.v[1])/2*s/2-#tostring(self.v[1])-s//32
  self:ldaf(10,10,310,230,c[1])
  self:ldrr(xc-p//1-1,yc-p//1-1,xc+p//1+1,yc+p//1+1,s,c[2])
  self:ldrrf(xc-p*a//1,yc-p*a//1,xc+p*a//1,yc+p*a//1,s,c[3])
  self:ldft(self.v[1],xc-xo,yc+s,s/2,c[2])
  local xn=(#self.id*(s/2))/2-s//32
  self:ldft(self.id,xc-xn,yc-1.5*s,s/2,c[2])
  self:ldsw()
end

This draws a visual representation of a value with element name label, updating only when the frame flag self.f is set.

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