HTML canvas globalCompositeOperation Property
Voorbeeld
Teken rechthoeken met twee verschillende globalCompositeOperation-waarden. Rode rechthoeken zijn bestemmingsafbeeldingen . Blauwe rechthoeken zijn bronafbeeldingen :
source-over
bestemming-over
javascript:
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.fillStyle = "red";
ctx.fillRect(20, 20, 75, 50);
ctx.globalCompositeOperation = "source-over";
ctx.fillStyle = "blue";
ctx.fillRect(50, 50, 75, 50);
ctx.fillStyle = "red";
ctx.fillRect(150, 20, 75, 50);
ctx.globalCompositeOperation = "destination-over";
ctx.fillStyle = "blue";
ctx.fillRect(180, 50, 75, 50);
Browserondersteuning
De getallen in de tabel geven de eerste browserversie aan die de eigenschap volledig ondersteunt.
Property | |||||
---|---|---|---|---|---|
globalCompositeOperation | 4.0 | 9.0 | 3.6 | 4.0 | 10.1 |
Definitie en gebruik
De eigenschap globalCompositeOperation bepaalt of retourneert hoe een (nieuwe) bronafbeelding op een (bestaande) doelafbeelding wordt getekend.
source image = tekeningen die je op het canvas gaat plaatsen.
bestemmingsafbeelding = tekeningen die al op het canvas zijn geplaatst.
Standaardwaarde: | source-over |
---|---|
JavaScript-syntaxis: | context .globalCompositeOperation = "bron-in"; |
Eigendomswaarden
Value | Description | Play it |
---|---|---|
source-over | Default. Displays the source image over the destination image | |
source-atop | Displays the source image on top of the destination image. The part of the source image that is outside the destination image is not shown | |
source-in | Displays the source image in to the destination image. Only the part of the source image that is INSIDE the destination image is shown, and the destination image is transparent | |
source-out | Displays the source image out of the destination image. Only the part of the source image that is OUTSIDE the destination image is shown, and the destination image is transparent | |
destination-over | Displays the destination image over the source image | |
destination-atop | Displays the destination image on top of the source image. The part of the destination image that is outside the source image is not shown | |
destination-in | Displays the destination image in to the source image. Only the part of the destination image that is INSIDE the source image is shown, and the source image is transparent | |
destination-out | Displays the destination image out of the source image. Only the part of the destination image that is OUTSIDE the source image is shown, and the source image is transparent | |
lighter | Displays the source image + the destination image | |
copy | Displays the source image. The destination image is ignored | |
xor | The source image is combined by using an exclusive OR with the destination image |
Voorbeeld
Alle waarden van de globalCompositeOperation-eigenschap: