104 lines
3.1 KiB
JavaScript
104 lines
3.1 KiB
JavaScript
function Spectrum(el) {
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this.el = el;
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this.ctx = null;
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this.min = 0;
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this.max = 0;
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this.timer = 0;
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this.data = [];
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// Make sure canvas fills the container
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el.style.width = '100%';
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el.style.height = '100%';
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// Start with hidden spectrum display
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this.close();
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}
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Spectrum.prototype.update = function(data) {
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// Do not update if no redraw timer or no canvas
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if (!this.timer || (this.el.clientHeight == 0)) return;
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for(var j=0; j<data.length; ++j) {
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this.data[j] = j>=this.data.length || data[j]>this.data[j]?
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data[j] : this.data[j] + (data[j] - this.data[j]) / 10.0;
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}
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// this.min = Math.min(...data);
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this.min = waterfall_min_level - 5;
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this.max = Math.max(...data);
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};
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Spectrum.prototype.draw = function() {
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// Do not draw if no redraw timer or no canvas
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if (!this.timer || (this.el.clientHeight == 0)) return;
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var vis_freq = get_visible_freq_range();
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var vis_center = vis_freq.center;
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var vis_start = 0.5 - (center_freq - vis_freq.start) / bandwidth;
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var vis_end = 0.5 - (center_freq - vis_freq.end) / bandwidth;
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var data_start = Math.round(fft_size * vis_start);
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var data_end = Math.round(fft_size * vis_end);
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var data_width = data_end - data_start;
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var data_height = Math.abs(this.max - this.min);
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var spec_width = this.el.offsetWidth;
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var spec_height = this.el.offsetHeight;
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// If canvas got resized, or no context yet...
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if (!this.ctx || spec_width!=this.el.width || spec_height!=this.el.height) {
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this.el.width = spec_width;
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this.el.height = spec_height;
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this.ctx = this.el.getContext("2d");
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this.ctx.fillStyle = "rgba(255, 255, 255, 0.4)";
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}
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// Clear canvas to transparency
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this.ctx.clearRect(0, 0, spec_width, spec_height);
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if(spec_width < data_width) {
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var x_ratio = data_width / spec_width;
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var y_ratio = spec_height / data_height;
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for(var x=0; x<spec_width; x++) {
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var y = (this.data[data_start + ((x * x_ratio) | 0)] - this.min) * y_ratio;
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this.ctx.fillRect(x, spec_height, 1, -y);
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}
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} else {
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var x_ratio = spec_width / data_width;
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var y_ratio = spec_height / data_height;
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for(var x=0; x<data_width; x++) {
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var y = (this.data[data_start + x] - this.min) * y_ratio;
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this.ctx.fillRect(x * x_ratio, spec_height, x_ratio, -y);
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}
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}
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};
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Spectrum.prototype.close = function() {
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// Hide container
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$('.openwebrx-spectrum-container').removeClass('expanded');
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// Stop redraw timer
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if (this.timer) {
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clearInterval(this.timer);
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this.timer = 0;
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}
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// Clear spectrum data
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this.data = [];
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}
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Spectrum.prototype.open = function() {
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// Show container
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$('.openwebrx-spectrum-container').addClass('expanded');
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// Start redraw timer
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if (!this.timer) {
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var me = this;
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this.timer = setInterval(function() { me.draw(); }, 100);
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}
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}
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Spectrum.prototype.toggle = function() {
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// Toggle based on the current redraw timer state
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if (this.timer) this.close(); else this.open();
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};
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