canvas

问题 I'm trying to draw an image file into the canvas to compose my widget in Flutter. I did follow canvas documentation but a did not success. O Image docs, thay say that: To obtain an Image object, use instantiateImageCodec. I did try use instantiateImageCodec method, but i just get a Codec instance, not a Image How is the right way to get an instance of ui.Image to draw on canvas using canvas.drawImage Here is a snnipet of my code: Future<ui.Codec> _loadImage(AssetBundleImageKey key) async {

问题 I am working on a mobile application(ionic) where there is a field for user's signature. Users needs to sign with their finger in canvas. Now this application has web version, where they used topaz sigweb to do this. Now to save signature and to view in both ends i need some kind of conversion. I checked sigweb's documentation, they save the signature in ASCHII hex format. I am not sure if they are using any kind of internal encryption or not because i can not convert the hex string to any

问题 I am working on a mobile application(ionic) where there is a field for user's signature. Users needs to sign with their finger in canvas. Now this application has web version, where they used topaz sigweb to do this. Now to save signature and to view in both ends i need some kind of conversion. I checked sigweb's documentation, they save the signature in ASCHII hex format. I am not sure if they are using any kind of internal encryption or not because i can not convert the hex string to any

问题 I am working on a mobile application(ionic) where there is a field for user's signature. Users needs to sign with their finger in canvas. Now this application has web version, where they used topaz sigweb to do this. Now to save signature and to view in both ends i need some kind of conversion. I checked sigweb's documentation, they save the signature in ASCHII hex format. I am not sure if they are using any kind of internal encryption or not because i can not convert the hex string to any

问题 I have some JS that makes some manipulations with images. I want to have pixelart-like graphics, so I had to enlarge original images in graphics editor. But I think it'd be good idea to make all the manipulations with the small image and then enlarge it with html5 functionality. This will save bunch of processing time (because now my demo ( warning : domain-name may cause some issues at work etc) loads extremely long in Firefox, for example). But when I try to resize the image, it gets

问题 When I first click the button it doesn't work. On my second click it downloads 1 picture. My 3rd click it downloads 2 pictures. On my 4th click it downloads 3 pictures. So 1-0, 2-1, 3-2, 4-3. They are also downloaded immediately, it doesn't ask where to save. js: function xyz(){ const text =canvas.api.getCanvasAsImage(); const download = document.getElementById('download'); download.addEventListener('click', function(e) { var link = document.createElement('a'); link.download = 'download.png';

问题 When I first click the button it doesn't work. On my second click it downloads 1 picture. My 3rd click it downloads 2 pictures. On my 4th click it downloads 3 pictures. So 1-0, 2-1, 3-2, 4-3. They are also downloaded immediately, it doesn't ask where to save. js: function xyz(){ const text =canvas.api.getCanvasAsImage(); const download = document.getElementById('download'); download.addEventListener('click', function(e) { var link = document.createElement('a'); link.download = 'download.png';

问题 When I first click the button it doesn't work. On my second click it downloads 1 picture. My 3rd click it downloads 2 pictures. On my 4th click it downloads 3 pictures. So 1-0, 2-1, 3-2, 4-3. They are also downloaded immediately, it doesn't ask where to save. js: function xyz(){ const text =canvas.api.getCanvasAsImage(); const download = document.getElementById('download'); download.addEventListener('click', function(e) { var link = document.createElement('a'); link.download = 'download.png';

来源： https://stackoverflow.com/questions/64352407/how-to-get-correct-coordinates-on-canvas-in-android-chrome

来源： https://stackoverflow.com/questions/61478157/how-do-you-play-a-canvas-in-a-video-element