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high-res scroll events for the waterfall zoom

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This commit is contained in:
Jakob Ketterl 2022-06-17 19:42:40 +02:00
parent 8532d9048e
commit 08188527ce
1 changed files with 16 additions and 1 deletions
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17
htdocs/openwebrx.js
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@ -614,10 +614,25 @@ function get_relative_x(evt) {
return relativeX - zoom_offset_px; return relativeX - zoom_offset_px;
} }
var wheel_delta_remainder = 0;
function canvas_mousewheel(evt) { function canvas_mousewheel(evt) {
var dir = (evt.deltaY / Math.abs(evt.deltaY)) > 0;
// deltaMode 0 means pixels instead of lines
if ('deltaMode' in evt && evt.deltaMode === 0) {
wheel_delta_remainder += evt.deltaY / 50;
console.info(wheel_delta_remainder);
if (wheel_delta_remainder >= 1) {
dir = true;
wheel_delta_remainder -= 1;
} else if (wheel_delta_remainder < 0) {
dir = false;
wheel_delta_remainder += 1;
} else return;
wheel_delta_remainder %= 1;
}
if (!waterfall_setup_done) return; if (!waterfall_setup_done) return;
var relativeX = get_relative_x(evt); var relativeX = get_relative_x(evt);
var dir = (evt.deltaY / Math.abs(evt.deltaY)) > 0;
zoom_step(dir, relativeX, zoom_center_where_calc(evt.pageX)); zoom_step(dir, relativeX, zoom_center_where_calc(evt.pageX));
evt.preventDefault(); evt.preventDefault();
} }