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Bangle.js: fills the display with a color disc
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| // fills the display of a Bangle.js with a color disc | |
| Bangle.setLCDMode(); // use normal display mode | |
| g.clear(); | |
| /**** HSVtoRGB (especially for Bangle.js and its RGB565 encoding) ****/ | |
| // see https://en.wikipedia.org/wiki/HSL_and_HSV#HSV_to_RGB | |
| function HSVtoRGB (h, s, v) { | |
| let c = v*s; | |
| let k = h/60; | |
| let x = c*(1 - Math.abs(k%2 - 1)); | |
| let r, g, b; | |
| switch (true) { | |
| case (k >=0) && (k <= 1): r = c; g = x; b = 0; break; | |
| case (k > 1) && (k <= 2): r = x; g = c; b = 0; break; | |
| case (k > 2) && (k <= 3): r = 0; g = c; b = x; break; | |
| case (k > 3) && (k <= 4): r = 0; g = x; b = c; break; | |
| case (k > 4) && (k <= 5): r = x; g = 0; b = c; break; | |
| case (k > 5) && (k <= 6): r = c; g = 0; b = x; break; | |
| } | |
| let m = v-c; | |
| return [ | |
| Math.round(31*(r+m)), Math.round(63*(g+m)), Math.round(31*(b+m)) | |
| ]; | |
| } | |
| /**** Rad2Deg ****/ | |
| function Rad2Deg (AngleInRad) { | |
| let AngleInDeg = (180*AngleInRad/Math.PI) % 360; | |
| return (AngleInDeg < 0 ? 360+AngleInDeg : AngleInDeg); | |
| } | |
| /**** draw color disc ****/ | |
| const Width = g.getWidth(), CenterX = Math.floor(Width)/2; | |
| const Height = g.getHeight(), CenterY = Math.floor(Height)/2; | |
| const Radius = Math.min(CenterX,CenterY), RadiusSquared = Radius*Radius; | |
| const xMin = CenterX-Radius, xMax = CenterX+Radius; | |
| const yMin = CenterY-Radius, yMax = CenterY+Radius; | |
| const Value = 1.0; | |
| for (let yOffset = -Radius; yOffset <= Radius; yOffset++) { | |
| for (let xOffset = -Radius; xOffset <= Radius; xOffset++) { | |
| let OffsetSquared = xOffset*xOffset + yOffset*yOffset; | |
| if (OffsetSquared <= RadiusSquared) { | |
| let Hue = Rad2Deg(Math.atan2(yOffset,xOffset)); | |
| let Saturation = Math.sqrt(OffsetSquared)/Radius; | |
| let RGB = HSVtoRGB(Hue, Saturation, Value); | |
| let Color = RGB[0] << 11 | RGB[1] << 5 | RGB[2]; | |
| g.setPixel(Radius+xOffset,Radius+yOffset, Color); | |
| } | |
| } | |
| } |
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