knobs/knob2.py

   1 #!/usr/bin/env python
   2
   3 import cairo
   4 from math import pi, cos, sin
   5
   6 WIDTH, HEIGHT = 40, 40
   7 x, y = WIDTH / 2, HEIGHT / 2
   8 lwidth = WIDTH / 10
   9 radius = WIDTH / 2 - lwidth
  10 radiusplus = radius + lwidth / 2
  11 radiusminus = radius - lwidth / 2
  12 radiusminus2 = radius - lwidth
  13 radiusminus3 = radius - lwidth * 3 / 2
  14 radiusint = (radius - lwidth / 2) * 0.25
  15 value = 0.7
  16 arrow = WIDTH / 10
  17 phases = 65
  18
  19 # Setup Cairo
  20 surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, phases * WIDTH, HEIGHT * 4)
  21 ctx = cairo.Context(surface)
  22 ctx.set_source_rgba(0.75, 0.75, 0.75, 0)
  23 ctx.rectangle(0, 0, phases * WIDTH, 4 * HEIGHT)
  24 ctx.fill()
  25
  26 for variant in range(0, 4):
  27     x = WIDTH / 2
  28     y = HEIGHT * (variant + 0.5)
  29     for phase in range(0, phases):
  30         # Draw out the triangle using absolute coordinates
  31         value = phase * 1.0 / (phases - 1)
  32         if variant != 3:
  33             sangle = (180 - 45)*pi/180
  34             eangle = (360 + 45)*pi/180
  35             nleds = 31
  36         else:
  37             sangle = (270)*pi/180
  38             eangle = (270 + 360)*pi/180
  39             nleds = 32
  40         vangle = sangle + value * (eangle - sangle)
  41         c, s = cos(vangle), sin(vangle)
  42
  43         midled = (nleds - 1) / 2
  44         midphase = (phases - 1) / 2
  45         thresholdP = midled + 1 + ((phase - midphase - 1) * 1.0 * (nleds - midled - 2) / (phases - midphase - 2))
  46         thresholdN = midled - 1 - ((midphase - 1 - phase) * 1.0 * (nleds - midled - 2) / (midphase - 1))
  47
  48         spacing = pi / nleds
  49         for led in range(0, nleds):
  50             if variant == 3:
  51                 adelta = (eangle - sangle) / (nleds)
  52             else:
  53                 adelta = (eangle - sangle - spacing) / (nleds - 1)
  54             lit = False
  55             glowlit = False
  56             glowval = 0.5
  57             hilite = False
  58             lvalue = led * 1.0 / (nleds - 1)
  59             pvalue = phase * 1.0 / (phases - 1)
  60             if variant == 3:
  61                 # XXXKF works only for phases = 2 * leds
  62                 exled = phase / 2.0
  63                 lit = led == exled or (phase == phases - 1 and led == 0)
  64                 glowlit = led == (exled + 0.5) or led == (exled - 0.5)
  65                 glowval = 0.8
  66                 hilite = (phase % ((phases - 1) / 4)) == 0
  67             if variant == 0: lit = (pvalue == 1.0) or pvalue > lvalue
  68             if variant == 1:
  69                 if led == midled:
  70                     lit = (phase == midphase)
  71                     #glowlit = (phase < midphase and thresholdN >= midled - 1) or (phase > midphase and thresholdP <= midled + 1)
  72                     glowlit = False
  73                     hilite = True
  74                 elif led > midled and phase > midphase:
  75                     # led = [midled + 1, nleds - 1]
  76                     # phase = [midphase + 1, phases - 1]
  77                     lit = led <= thresholdP
  78                     glowlit = led <= thresholdP + 1
  79                     glowval = 0.4
  80                 elif led < midled and phase < midphase:
  81                     lit = led >= thresholdN
  82                     glowlit = led >= thresholdN - 1
  83                     glowval = 0.4
  84                 else:
  85                     lit = False
  86             if variant == 2: lit = pvalue == 0 or pvalue < lvalue
  87             if not lit:
  88                 if not glowlit:
  89                     ctx.set_source_rgb(0, 0, 0)
  90                 else:
  91                     ctx.set_source_rgb(1 * glowval, 0.5 * glowval, 0)
  92             else:
  93                 if hilite:
  94                     ctx.set_source_rgb(1, 1, 0)
  95                 else:
  96                     ctx.set_source_rgb(1, 0.5, 0)
  97             ctx.set_line_width(3)
  98             if hilite:
  99                 ctx.set_line_width(4)
 100             ctx.arc(x, y, radius, sangle + adelta * led, sangle + adelta * led + spacing)
 101             ctx.stroke()
 102
 103         #ctx.set_line_width(lwidth)
 104         #ctx.set_source_rgb(1, 0.5, 0)
 105         #ctx.arc(x, y, radius, sangle, vangle)
 106         #ctx.line_to(x + radiusint * c, y + radiusint * s)
 107         #ctx.stroke()
 108
 109         grad = cairo.LinearGradient(x - radius / 2, y - radius / 2, x + radius / 2, y + radius / 2)
 110         #grad.add_color_stop_rgb(0.0, 0.5, 0.5, 0.5)
 111         #grad.add_color_stop_rgb(1.0, 0.8, 0.8, 0.8)
 112         grad.add_color_stop_rgb(0.0, 0.5, 0.5, 0.5)
 113         grad.add_color_stop_rgb(1.0, 0.8, 0.8, 0.8)
 114         ctx.set_source(grad)
 115         # ctx.set_source_rgb(0.8, 0.8, 0.8)
 116         ctx.set_line_width(2)
 117         ctx.arc(x, y, radiusminus2, 0, 2 * pi)
 118         ctx.fill()
 119
 120         grad = cairo.LinearGradient(x - radius / 2, y - radius / 2, x + radius / 2, y + radius / 2)
 121         grad.add_color_stop_rgb(0.0, 0.8, 0.8, 0.8)
 122         grad.add_color_stop_rgb(1.0, 0.5, 0.5, 0.5)
 123         ctx.set_source(grad)
 124         ctx.arc(x, y, radiusminus3, 0, 2 * pi)
 125         ctx.fill()
 126         ctx.set_source_rgb(0, 0, 0)
 127         ctx.set_line_width(2)
 128         ctx.arc(x, y, radiusminus2, 0, 2 * pi)
 129         ctx.stroke()
 130
 131         ctx.set_source_rgba(0, 0, 0, 0.5)
 132         ctx.set_line_width(1)
 133         mtx = ctx.get_matrix()
 134         ctx.translate(x + radiusminus2 * c, y + radiusminus2 * s)
 135         ctx.rotate(vangle)
 136         ctx.move_to(0, 0)
 137         ctx.line_to(-radius/2, 0)
 138         ctx.stroke()
 139         ctx.set_matrix(mtx)
 140         x += WIDTH
 141
 142 #ctx.set_source_rgb(1, 0.5, 0)
 143 #ctx.line_to(x + radiusplus * c, y + radiusplus * s)
 144 #ctx.stroke()
 145
 146 # Output a PNG file
 147 surface.write_to_png("knob.png")