joachim/openwebrx-clone
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initialize canvas on demand to avoid overlap when changing parameters

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This commit is contained in:
Jakob Ketterl 2021-02-24 00:58:50 +01:00
parent f69d78926e
commit 710a18aae3
1 changed files with 10 additions and 9 deletions
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19
htdocs/openwebrx.js
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@ -1064,14 +1064,14 @@ var canvas_context;
var canvases = []; var canvases = [];
var canvas_default_height = 200; var canvas_default_height = 200;
var canvas_container; var canvas_container;
var canvas_actual_line; var canvas_actual_line = -1;
function add_canvas() { function add_canvas() {
var new_canvas = document.createElement("canvas"); var new_canvas = document.createElement("canvas");
new_canvas.width = fft_size; new_canvas.width = fft_size;
new_canvas.height = canvas_default_height; new_canvas.height = canvas_default_height;
canvas_actual_line = canvas_default_height - 1; canvas_actual_line = canvas_default_height;
new_canvas.openwebrx_top = (-canvas_default_height + 1); new_canvas.openwebrx_top = -canvas_default_height;
new_canvas.style.top = new_canvas.openwebrx_top.toString() + "px"; new_canvas.style.top = new_canvas.openwebrx_top.toString() + "px";
canvas_context = new_canvas.getContext("2d"); canvas_context = new_canvas.getContext("2d");
canvas_container.appendChild(new_canvas); canvas_container.appendChild(new_canvas);
@ -1093,7 +1093,6 @@ function init_canvas_container() {
canvas_container.addEventListener("wheel", canvas_mousewheel, false); canvas_container.addEventListener("wheel", canvas_mousewheel, false);
var frequency_container = $("#openwebrx-frequency-container"); var frequency_container = $("#openwebrx-frequency-container");
frequency_container.on("wheel", canvas_mousewheel, false); frequency_container.on("wheel", canvas_mousewheel, false);
add_canvas();
} }
canvas_maxshift = 0; canvas_maxshift = 0;
@ -1139,6 +1138,9 @@ function waterfall_add(data) {
waterfallColorsContinuous(level); waterfallColorsContinuous(level);
} }
// create new canvas if the current one is full (or there isn't one)
if (canvas_actual_line <= 0) add_canvas();
//Add line to waterfall image //Add line to waterfall image
var oneline_image = canvas_context.createImageData(w, 1); var oneline_image = canvas_context.createImageData(w, 1);
for (var x = 0; x < w; x++) { for (var x = 0; x < w; x++) {
@ -1148,18 +1150,17 @@ function waterfall_add(data) {
} }
//Draw image //Draw image
canvas_context.putImageData(oneline_image, 0, canvas_actual_line--); canvas_context.putImageData(oneline_image, 0, --canvas_actual_line);
shift_canvases(); shift_canvases();
if (canvas_actual_line < 0) add_canvas();
} }
function waterfall_clear() { function waterfall_clear() {
while (canvases.length) //delete all canvases //delete all canvases
{ while (canvases.length) {
var x = canvases.shift(); var x = canvases.shift();
x.parentNode.removeChild(x); x.parentNode.removeChild(x);
} }
add_canvas(); canvas_actual_line = -1;
} }
function openwebrx_resize() { function openwebrx_resize() {