html5-canvas

问题 This question is for a deeper understanding of my previous question about large size Canvas animation. The question is here: Repeat HTML canvas element (box) to fill whole viewport I am trying to understand the logic behind the TypedArray - Uint8ClampedArray. I will first start with my research and get to the question itself later. So, ImageData represents the pixel data of the HTML5 Canvas. It allows for much faster performance and is good for heavy animations. After we have our ImageData

问题 This question is for a deeper understanding of my previous question about large size Canvas animation. The question is here: Repeat HTML canvas element (box) to fill whole viewport I am trying to understand the logic behind the TypedArray - Uint8ClampedArray. I will first start with my research and get to the question itself later. So, ImageData represents the pixel data of the HTML5 Canvas. It allows for much faster performance and is good for heavy animations. After we have our ImageData

问题 This question is for a deeper understanding of my previous question about large size Canvas animation. The question is here: Repeat HTML canvas element (box) to fill whole viewport I am trying to understand the logic behind the TypedArray - Uint8ClampedArray. I will first start with my research and get to the question itself later. So, ImageData represents the pixel data of the HTML5 Canvas. It allows for much faster performance and is good for heavy animations. After we have our ImageData

问题 I have a regular Chartjs doughnut chart with multiple datasets, using this code for the dataset: datasets: [ { label: 'Bugs', data: [ 60 , 6.6666666666667 , 33.333333333333 ], backgroundColor: ['#25CFE4', '#92E7F1', '#eeeeee'], }, { label: 'Fixes', data: [ 60 , 0.44444444444444 , 39.555555555556 ], backgroundColor: ['#514463', '#8C75AB', '#eeeeee'], }, { label: 'Redesigns', data: [ 33.333333333333 , 10.37037037037 , 56.296296296296 ], backgroundColor: ['#1B745F', '#40C1A0', '#eeeeee'], } ] };

问题 I have a regular Chartjs doughnut chart with multiple datasets, using this code for the dataset: datasets: [ { label: 'Bugs', data: [ 60 , 6.6666666666667 , 33.333333333333 ], backgroundColor: ['#25CFE4', '#92E7F1', '#eeeeee'], }, { label: 'Fixes', data: [ 60 , 0.44444444444444 , 39.555555555556 ], backgroundColor: ['#514463', '#8C75AB', '#eeeeee'], }, { label: 'Redesigns', data: [ 33.333333333333 , 10.37037037037 , 56.296296296296 ], backgroundColor: ['#1B745F', '#40C1A0', '#eeeeee'], } ] };

问题 If you get JSON data from Instagram's API you will find a media_preview key, the value of which is some Base64-encoded data. It really looks like some very small preview binary data. Maybe compressed. Take this post for example. It's just a black square and its preview is very small. Look at its JSON: data['graphql']['media_preview'] = "ACoq5miiigAooooAKKKKACiiigAooooAKKKKACiiigAooooAKKKKAP/Z" I could not reverse the code and find out how Instagram uses this data. What should I do to create a

问题 How to get a sections of a single image using javascript and store it in an array, and later display randomly on html5 canvas. 回答1: You can use the clipping parameters of the drawImage() method and draw your clipped image onto a dynamically created canvas. An example could be: function getClippedRegion(image, x, y, width, height) { var canvas = document.createElement('canvas'), ctx = canvas.getContext('2d'); canvas.width = width; canvas.height = height; // source region dest. region ctx

问题 I want to get all the x,y coordinates between 2 given points, on a straight line. While this seems like such an easy task, I can't seem to get my head around it. So, for example: Point 1: (10,5) Point 2: (15,90) 回答1: Edit: The solution below only applies from a geometrical point of view. Drawing on a screen is different than theoretical geometry, you should listen to the people suggesting Bresenham's algorithm. Given, two points, and knowing that the line's equation is y = m*x + b , where m

问题 I want to get all the x,y coordinates between 2 given points, on a straight line. While this seems like such an easy task, I can't seem to get my head around it. So, for example: Point 1: (10,5) Point 2: (15,90) 回答1: Edit: The solution below only applies from a geometrical point of view. Drawing on a screen is different than theoretical geometry, you should listen to the people suggesting Bresenham's algorithm. Given, two points, and knowing that the line's equation is y = m*x + b , where m

问题 I want to get all the x,y coordinates between 2 given points, on a straight line. While this seems like such an easy task, I can't seem to get my head around it. So, for example: Point 1: (10,5) Point 2: (15,90) 回答1: Edit: The solution below only applies from a geometrical point of view. Drawing on a screen is different than theoretical geometry, you should listen to the people suggesting Bresenham's algorithm. Given, two points, and knowing that the line's equation is y = m*x + b , where m