Detecting image events for non-transparent pixels only (drawHitFromCache) in Vue Konva
So I'm basically trying to reproduce this behavior - detecting events for non-transparent pixels only (as seen when hovering over the lion) - but in vue-konva.
Here is the demo I'm working with. It basically just loads the image of lion and attaches the mouse events to it.
According to the doc, in order to have the event detection only for non-transparent pixels, I have to call methods cache() and drawHitFromCache() on the image object of lion.
At what point in code should these two methods be called in Vue? When I try to call them in the onload callback of the Image (see the commented lines 46-47 in the demo), I get the following errors:
Konva error: Width or height of caching configuration equals 0. Caching is ignored.
and
Cannot read property 'scene' of undefined
Thank you!
javascript vue.js konvajs
asked Nov 26 '18 at 16:16
ArxArx
26329
add a comment |
So I'm basically trying to reproduce this behavior - detecting events for non-transparent pixels only (as seen when hovering over the lion) - but in vue-konva.
Here is the demo I'm working with. It basically just loads the image of lion and attaches the mouse events to it.
According to the doc, in order to have the event detection only for non-transparent pixels, I have to call methods cache() and drawHitFromCache() on the image object of lion.
At what point in code should these two methods be called in Vue? When I try to call them in the onload callback of the Image (see the commented lines 46-47 in the demo), I get the following errors:
Konva error: Width or height of caching configuration equals 0. Caching is ignored.
and
Cannot read property 'scene' of undefined
Thank you!
javascript vue.js konvajs
asked Nov 26 '18 at 16:16
ArxArx
26329
add a comment |
So I'm basically trying to reproduce this behavior - detecting events for non-transparent pixels only (as seen when hovering over the lion) - but in vue-konva.
Here is the demo I'm working with. It basically just loads the image of lion and attaches the mouse events to it.
According to the doc, in order to have the event detection only for non-transparent pixels, I have to call methods cache() and drawHitFromCache() on the image object of lion.
At what point in code should these two methods be called in Vue? When I try to call them in the onload callback of the Image (see the commented lines 46-47 in the demo), I get the following errors:
Konva error: Width or height of caching configuration equals 0. Caching is ignored.
and
Cannot read property 'scene' of undefined
Thank you!
javascript vue.js konvajs
asked Nov 26 '18 at 16:16
ArxArx
26329
So I'm basically trying to reproduce this behavior - detecting events for non-transparent pixels only (as seen when hovering over the lion) - but in vue-konva.
Here is the demo I'm working with. It basically just loads the image of lion and attaches the mouse events to it.
According to the doc, in order to have the event detection only for non-transparent pixels, I have to call methods cache() and drawHitFromCache() on the image object of lion.
At what point in code should these two methods be called in Vue? When I try to call them in the onload callback of the Image (see the commented lines 46-47 in the demo), I get the following errors:
Konva error: Width or height of caching configuration equals 0. Caching is ignored.
and
Cannot read property 'scene' of undefined
Thank you!
javascript vue.js konvajs
javascript vue.js konvajs
asked Nov 26 '18 at 16:16
ArxArx
26329
asked Nov 26 '18 at 16:16
ArxArx
26329
asked Nov 26 '18 at 16:16
ArxArx
26329
asked Nov 26 '18 at 16:16
ArxArx
26329
asked Nov 26 '18 at 16:16
ArxArx
26329
26329
add a comment |
add a comment |
1 Answer
1
active
oldest
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Vue may update properties of a component asynchronously. So when you are calling cache() you see Caching is ignored because a node is not updated yet, so Konva has no information about its size. To resolve the issue you may call cache in updated lifecycle method (when an image is loaded). Or you can cache the node on the next tick:
image.onload = () => {
// set image only when it is loaded
this.configImage.image = image;
this.$nextTick(() => {
this.$refs.staticImage.getNode().cache();
this.$refs.staticImage.getNode().drawHitFromCache();
});
};
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Vue may update properties of a component asynchronously. So when you are calling cache() you see Caching is ignored because a node is not updated yet, so Konva has no information about its size. To resolve the issue you may call cache in updated lifecycle method (when an image is loaded). Or you can cache the node on the next tick:
image.onload = () => {
// set image only when it is loaded
this.configImage.image = image;
this.$nextTick(() => {
this.$refs.staticImage.getNode().cache();
this.$refs.staticImage.getNode().drawHitFromCache();
});
};
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
add a comment |
Vue may update properties of a component asynchronously. So when you are calling cache() you see Caching is ignored because a node is not updated yet, so Konva has no information about its size. To resolve the issue you may call cache in updated lifecycle method (when an image is loaded). Or you can cache the node on the next tick:
image.onload = () => {
// set image only when it is loaded
this.configImage.image = image;
this.$nextTick(() => {
this.$refs.staticImage.getNode().cache();
this.$refs.staticImage.getNode().drawHitFromCache();
});
};
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
add a comment |
Vue may update properties of a component asynchronously. So when you are calling cache() you see Caching is ignored because a node is not updated yet, so Konva has no information about its size. To resolve the issue you may call cache in updated lifecycle method (when an image is loaded). Or you can cache the node on the next tick:
image.onload = () => {
// set image only when it is loaded
this.configImage.image = image;
this.$nextTick(() => {
this.$refs.staticImage.getNode().cache();
this.$refs.staticImage.getNode().drawHitFromCache();
});
};
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
Vue may update properties of a component asynchronously. So when you are calling cache() you see Caching is ignored because a node is not updated yet, so Konva has no information about its size. To resolve the issue you may call cache in updated lifecycle method (when an image is loaded). Or you can cache the node on the next tick:
image.onload = () => {
// set image only when it is loaded
this.configImage.image = image;
this.$nextTick(() => {
this.$refs.staticImage.getNode().cache();
this.$refs.staticImage.getNode().drawHitFromCache();
});
};
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
answered Nov 26 '18 at 21:38
lavrtonlavrton
7,43221231
7,43221231
add a comment |
add a comment |
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