HTML and CSS Reference
In-Depth Information
Listing 8.16. index.html—Change the composition mode in the draw() function
Video isn't the ideal format to experiment with composition modes because it's always a
fully opaque image, and in this example it's taking up all the pixels. But this simple im-
plementation will allow you to experiment and consider where you might use them in your
own projects.
step 3: Adjust the opacity of the video
The opacity is set with the .globalAlpha property. It should be a value between 0 and
1; in common with CSS, 1 is fully opaque and 0 is completely transparent. In your applic-
ation you can add an item to let the user set the value with a number input; add this code
after the <menu> element:
Opacity: <input type = "number" step= "0.1" min= "0" max= "1" value = "1.0" >
As before, you need to attach an event handler to this input and feed the results into
the draw() function through a variable. The following listing has the additional code
to capture the opacity and another new draw() function. Replace the draw() function
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