It is found that there is no response as long as the left,top of this picture is more than 150 pixels after pressing the picture. More than 40 days ago, I also encountered the same problem, I don't know what happened, but I also set the width and height of the picture. I find that sometimes my long button only pops up save and cancel menus, but sometimes there are very complete menus that pop up, such as sending to friends, saving, collecting, identifying QR codes, and canceling. If you don't believe it, you can simply press the phone around the screen and find it. Use, otherwise you can identify it according to the one below. You can take a look at it and leave a message if you have any questions. Ībout why the absolute location does not pop up, it should be a problem with the style, which causes the picture to have no height and does not trigger his longPress event. Omitting the table here, you can google, to give you a ladder. If you want to know the specific 'how to determine whether a picture contains a QR code?', then we have to talk about the positioning point of the QR code and the error correction mechanism.

If so, add an option of 'scan QR code' to the long press menu, of course. During this period of time, Wechat's built-in browser uses an algorithm to determine whether the picture is a QR code. Īs for why you know that he is a QR code, when you press the picture for a long time, you find that the first three menu options pop up first, and the scan QR code pops up after about 1 second. You can look at it as pseudo code implemented by Wechat. For Wechat's built-in browser, it is to implement a contextMenu, judge context.MediaType, and post a code for right-click picture menu in the chrome extension.

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