tlhotlha

tlhotlha(effect, [amount], [useWebGL])

tlhotlha changes the whole canvas at once. The effects are:

• BOPUTSWA — takes the colour out, leaving grey. Measured: a red dot [255, 0, 0] becomes [54, 54, 54].
• RIBEGA — turns every colour into its opposite. Measured: [255, 0, 0] becomes [0, 255, 255].
• MOLELWANE — every dot becomes either white or black, with nothing in between.
• PHIFALO — blurs the picture. A second number is how much; with no number it is the same as tlhotlha(PHIFALO, 3) — measured.
• GO_SE_BONALE — removes all transparency. On an already-opaque canvas it does nothing; on a see-through one, [255, 0, 0, 128] becomes [255, 0, 0, 255] — measured.
• POSTERIZE — cuts the number of colours down. It does not change colours already at the extremes (0 or 255); it changes the ones in between.

It does not need balaDiphikisele first — measured.

⚠ An unknown name throws a readable error: “Unknown filter: …”. That is unlike seeloSaMotswako, which throws an unreadable one.

⚠ DILATE and ERODE are not in Bopa, and the reason is real. On the canvas, the two do exactly the same thing — and it is not growing or shrinking: they shift the picture by one dot. Measured — a 20×20 black square stays 400 dots after either, just moved. On a picture itself they work correctly.

Parameters

Name	Type	Description
mokgwa	konoketsi	BOPUTSWA, RIBEGA, MOLELWANE, PHIFALO, GO_SE_BONALE or POSTERIZE.
bogolo	palo	An amount, optional — used only by PHIFALO and POSTERIZE.
dirisaWebGL (optional)	nnetemaaka	Defaults to nnete (WebGL). Pass maaka last to use CPU filters when WebGL is unavailable, as these examples do.

Examples

One picture, two effects

Rerun ↻Open in editor ↗

tiro setaLoeto() {
  thalaKanefase(400, 160);
  bokamorago(245);

  diri mokolwane = letela tlisaSetshwantsho('mokolwane.png');
  thalaSetshwantsho(mokolwane, 20, 15, 130, 130);
  thalaSetshwantsho(mokolwane, 250, 15, 130, 130);

  tlhotlha(RIBEGA, maaka);

  tlhalosa('Mekolwane e mebedi, ka bobedi e ribegilwe mebala, mo kanefaseng e ntsho.');
}

See also

BOPUTSWA, RIBEGA, PHIFALO, MOLELWANE, balaDiphikisele