mirror of https://github.com/espruino/BangleApps
67 lines
2.6 KiB
JavaScript
67 lines
2.6 KiB
JavaScript
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var Hand = require("fontclock.hand.js");
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class ThinHand extends Hand {
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/**
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* The thin hand is created from a simple line, so its easy and fast
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* to draw.
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*/
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constructor(centerX,
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centerY,
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length,
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tolerance,
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draw_test,
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color_bg_supplier,
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color_fg_supplier){
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super();
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this.centerX = centerX;
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this.centerY = centerY;
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this.length = length;
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this.color_bg_supplier = color_bg_supplier;
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this.color_fg_supplier = color_fg_supplier;
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// The last x and y coordinates (not the centre) of the last draw
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this.last_x = centerX;
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this.last_y = centerY;
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// tolerance is the angle tolerance (from the last draw)
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// in radians for a redraw to be called.
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this.tolerance = tolerance;
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// draw test is a predicate (angle, time). This is called
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// when the hand thinks that it does not have to draw (from its internal tests)
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// to see if it has to draw because of another object.
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this.draw_test = draw_test;
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// The current angle of the hand. Set to -1 initially
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this.angle = -1;
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this.last_draw_time = null;
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this.active = false;
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}
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// method to move the hand to a new angle
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moveTo(angle){
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// first test to see of the angle called is beyond the tolerance
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// for a redraw
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if(Math.abs(angle - this.angle) > this.tolerance ||
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// and then call the predicate to see if a redraw is needed
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this.draw_test(this.angle,this.last_draw_time) ){
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// rub out the old hand line
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var background = this.color_bg_supplier();
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g.setColor(background[0],background[1],background[2]);
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g.drawLine(this.centerX, this.centerY, this.last_x, this.last_y);
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// Now draw the new hand line
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var hand_color = this.color_fg_supplier();
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g.setColor(hand_color[0],hand_color[1],hand_color[2]);
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var x2 = this.centerX + this.length*Math.sin(angle);
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var y2 = this.centerY - this.length*Math.cos(angle);
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g.drawLine(this.centerX, this.centerY, x2, y2);
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// and store the last draw details for the next call
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this.last_x = x2;
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this.last_y = y2;
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this.angle = angle;
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this.last_draw_time = new Date();
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this.active = true;
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return true;
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} else {
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this.active = false;
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return false;
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}
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}
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}
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module.exports = ThinHand;
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