why zoom in and zoom out not working first time in react js?
Could you please tell me why zoom in and zoom out button not working first time.when I click button first time it not zoom in and not zoom out why ?
Here is my code
https://codesandbox.io/s/o4o98kwy0y
zoomIn = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale + zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
javascript reactjs
edited Nov 21 at 8:11
Tholle
33.7k53760
asked Nov 21 at 6:49
Joy
1097
add a comment |
Could you please tell me why zoom in and zoom out button not working first time.when I click button first time it not zoom in and not zoom out why ?
Here is my code
https://codesandbox.io/s/o4o98kwy0y
zoomIn = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale + zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
javascript reactjs
edited Nov 21 at 8:11
Tholle
33.7k53760
asked Nov 21 at 6:49
Joy
1097
add a comment |
Could you please tell me why zoom in and zoom out button not working first time.when I click button first time it not zoom in and not zoom out why ?
Here is my code
https://codesandbox.io/s/o4o98kwy0y
zoomIn = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale + zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
javascript reactjs
edited Nov 21 at 8:11
Tholle
33.7k53760
asked Nov 21 at 6:49
Joy
1097
Could you please tell me why zoom in and zoom out button not working first time.when I click button first time it not zoom in and not zoom out why ?
Here is my code
https://codesandbox.io/s/o4o98kwy0y
zoomIn = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale + zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}));
this.drawImage();
};
javascript reactjs
javascript reactjs
edited Nov 21 at 8:11
Tholle
33.7k53760
asked Nov 21 at 6:49
Joy
1097
edited Nov 21 at 8:11
Tholle
33.7k53760
asked Nov 21 at 6:49
Joy
1097
edited Nov 21 at 8:11
Tholle
33.7k53760
edited Nov 21 at 8:11
Tholle
33.7k53760
edited Nov 21 at 8:11
Tholle
33.7k53760
33.7k53760
asked Nov 21 at 6:49
Joy
1097
asked Nov 21 at 6:49
Joy
1097
asked Nov 21 at 6:49
Joy
1097
1097
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
It is because you are setting state and immediately drawing the image,
What you need is setState callback, Here is an example of it
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}), () => {
this.drawImage();
});
};
Updated code in your link
edited Nov 21 at 8:11
Tholle
33.7k53760
answered Nov 21 at 6:57
Just code
8,61642966
good thanks for help
– Joy
Nov 21 at 6:59
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
It is because you are setting state and immediately drawing the image,
What you need is setState callback, Here is an example of it
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}), () => {
this.drawImage();
});
};
Updated code in your link
edited Nov 21 at 8:11
Tholle
33.7k53760
answered Nov 21 at 6:57
Just code
8,61642966
good thanks for help
– Joy
Nov 21 at 6:59
add a comment |
It is because you are setting state and immediately drawing the image,
What you need is setState callback, Here is an example of it
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}), () => {
this.drawImage();
});
};
Updated code in your link
edited Nov 21 at 8:11
Tholle
33.7k53760
answered Nov 21 at 6:57
Just code
8,61642966
good thanks for help
– Joy
Nov 21 at 6:59
add a comment |
It is because you are setting state and immediately drawing the image,
What you need is setState callback, Here is an example of it
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}), () => {
this.drawImage();
});
};
Updated code in your link
edited Nov 21 at 8:11
Tholle
33.7k53760
answered Nov 21 at 6:57
Just code
8,61642966
It is because you are setting state and immediately drawing the image,
What you need is setState callback, Here is an example of it
zoomOut = () => {
console.log("zoom in");
const { currentAngle, currentScale, zoomDelta } = this.state;
const c = currentScale - zoomDelta;
this.setState(state => ({
...state,
currentScale: c
}), () => {
this.drawImage();
});
};
Updated code in your link
edited Nov 21 at 8:11
Tholle
33.7k53760
answered Nov 21 at 6:57
Just code
8,61642966
edited Nov 21 at 8:11
Tholle
33.7k53760
edited Nov 21 at 8:11
Tholle
33.7k53760
edited Nov 21 at 8:11
Tholle
33.7k53760
33.7k53760
answered Nov 21 at 6:57
Just code
8,61642966
answered Nov 21 at 6:57
Just code
8,61642966
answered Nov 21 at 6:57
Just code
8,61642966
8,61642966
good thanks for help
– Joy
Nov 21 at 6:59
add a comment |
good thanks for help
– Joy
Nov 21 at 6:59
good thanks for help
– Joy
Nov 21 at 6:59
good thanks for help
– Joy
Nov 21 at 6:59
add a comment |
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