joachim/openwebrx-clone
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split waterfall over multiple canvas elements to increase maximum fft resolution

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J.W. Jagersma 2020-09-13 06:47:05 +02:00
parent cc385f851f
commit 0987a67382
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GPG Key ID: 438BF81BA7510C54
2 changed files with 40 additions and 21 deletions
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9
htdocs/css/openwebrx.css
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@ -294,14 +294,21 @@ input[type=range]:disabled {
flex-grow: 1;
}
#webrx-canvas-container div
{
position: relative;
overflow: visible;
width: 100%;
}
#webrx-canvas-container canvas
{
position: absolute;
border-style: none;
image-rendering: crisp-edges;
image-rendering: -webkit-optimize-contrast;
width: 100%;
height: 200px;
pointer-events: none;
}
#openwebrx-log-scroll

34
htdocs/openwebrx.js
View File

@ -1226,22 +1226,30 @@ function color_between(first, second, percent) {
}
var canvas_context;
var canvas_max_width = 8192;
var canvas_subcontainer;
var canvases = [];
var canvas_default_height = 200;
var canvas_container;
var canvas_actual_line;
function add_canvas() {
canvas_subcontainer = document.createElement("div");
var n = fft_size / canvas_max_width;
var w = 100 / n;
for (var i = 0; i < n; ++i) {
var new_canvas = document.createElement("canvas");
new_canvas.width = fft_size;
new_canvas.width = Math.min(fft_size, canvas_max_width);
new_canvas.height = canvas_default_height;
new_canvas.style.width = w + '%';
new_canvas.style.marginLeft = (w * i) + '%';
canvas_actual_line = canvas_default_height - 1;
new_canvas.openwebrx_top = (-canvas_default_height + 1);
new_canvas.style.top = new_canvas.openwebrx_top.toString() + "px";
canvas_context = new_canvas.getContext("2d");
canvas_container.appendChild(new_canvas);
canvases.push(new_canvas);
canvas_subcontainer.appendChild(new_canvas);
}
canvas_subcontainer.openwebrx_top = (-canvas_default_height + 1);
canvas_subcontainer.style.top = canvas_subcontainer.openwebrx_top.toString() + "px";
canvas_container.appendChild(canvas_subcontainer);
canvases.push(canvas_subcontainer);
while (canvas_container && canvas_container.clientHeight + canvas_default_height * 2 < canvases.length * canvas_default_height) {
var c = canvases.shift();
if (!c) break;
@ -1291,7 +1299,6 @@ function waterfall_init() {
function waterfall_add(data) {
if (!waterfall_setup_done) return;
var w = fft_size;
if (waterfall_measure_minmax_now) {
var levels = waterfall_measure_minmax_do(data);
@ -1305,16 +1312,21 @@ function waterfall_add(data) {
waterfallColorsContinuous(level);
}
//Add line to waterfall image
//Add line to waterfall
var w = Math.min(fft_size, canvas_max_width);
for (var j = 0; j < fft_size / canvas_max_width; ++j) {
var canvas_context = canvas_subcontainer.childNodes[j].getContext("2d");
var oneline_image = canvas_context.createImageData(w, 1);
for (var x = 0; x < w; x++) {
var color = waterfall_mkcolor(data[x]);
var color = waterfall_mkcolor(data[x + canvas_max_width * j]);
for (i = 0; i < 3; i++) oneline_image.data[x * 4 + i] = color[i];
oneline_image.data[x * 4 + 3] = 255;
}
//Draw image
canvas_context.putImageData(oneline_image, 0, canvas_actual_line--);
canvas_context.putImageData(oneline_image, 0, canvas_actual_line);
}
--canvas_actual_line;
shift_canvases();
if (canvas_actual_line < 0) add_canvas();
}