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why zoom in and zoom out not working first time in react js?
1
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 '18 at 8:11
Tholle
34.4k53860
asked Nov 21 '18 at 6:49
JoyJoy
1097
add a comment |
1
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 '18 at 8:11
Tholle
34.4k53860
asked Nov 21 '18 at 6:49
JoyJoy
1097
add a comment |
1
1
1
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 '18 at 8:11
Tholle
34.4k53860
asked Nov 21 '18 at 6:49
JoyJoy
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 '18 at 8:11
Tholle
34.4k53860
asked Nov 21 '18 at 6:49
JoyJoy
1097
edited Nov 21 '18 at 8:11
Tholle
34.4k53860
asked Nov 21 '18 at 6:49
JoyJoy
1097
edited Nov 21 '18 at 8:11
Tholle
34.4k53860
edited Nov 21 '18 at 8:11
Tholle
34.4k53860
edited Nov 21 '18 at 8:11
Tholle
34.4k53860
34.4k53860
asked Nov 21 '18 at 6:49
JoyJoy
1097
asked Nov 21 '18 at 6:49
JoyJoy
1097
asked Nov 21 '18 at 6:49
JoyJoy
1097
1097
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
0
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 '18 at 8:11
Tholle
34.4k53860
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
good thanks for help
– Joy
Nov 21 '18 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
0
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 '18 at 8:11
Tholle
34.4k53860
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
good thanks for help
– Joy
Nov 21 '18 at 6:59
add a comment |
0
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 '18 at 8:11
Tholle
34.4k53860
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
good thanks for help
– Joy
Nov 21 '18 at 6:59
add a comment |
0
0
0
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 '18 at 8:11
Tholle
34.4k53860
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
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 '18 at 8:11
Tholle
34.4k53860
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
edited Nov 21 '18 at 8:11
Tholle
34.4k53860
edited Nov 21 '18 at 8:11
Tholle
34.4k53860
edited Nov 21 '18 at 8:11
Tholle
34.4k53860
34.4k53860
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
answered Nov 21 '18 at 6:57
Just codeJust code
10.4k53066
10.4k53066
good thanks for help
– Joy
Nov 21 '18 at 6:59
add a comment |
good thanks for help
– Joy
Nov 21 '18 at 6:59
good thanks for help
– Joy
Nov 21 '18 at 6:59
good thanks for help
– Joy
Nov 21 '18 at 6:59
add a comment |
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