HTML and CSS Reference
In-Depth Information
Animated Gradients
Before we leave the topic of text, we would like to introduce some animation into the mix.
Everything you have seen so far in this chapter has been pretty much static. While text on
HTML5 Canvas is really cool, it is not too far from what could be accomplished in standard
HTML. Static text is static, and its utility when not being styled with CSS (again, the Canvas
currently does not support CSS styling) might make you choose another solution for a pure
text application.
However, animation is where the Canvas shows its utility beyond standard HTML. For this
gradient fills. The gradient fills will “animate” by moving up in the text fill. The effect here
is similar to what old video game and computer systems (especially those from Atari) used to
create animated title screens.
Figure 3-12 shows what a single frame of the animation looks like on the Canvas.
Figure 3-12. Color cycle animation
The key to creating a gradient animation are the createLinearGradient() and gradi-
ent.addColorStop methods we discussed previously in this chapter, combined with the
setTimeout() game loop functionality we developed in Chapter 1 . First, we will set up a
or stops” that represent the colors in the gradient animation.
To get started, let's set up an animation loop:
function drawScreen () {
function gameLoop () {
window . setTimeout ( gameLoop , 20 );
drawScreen ()
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