手機適應螢幕簡單圖片處理演算法

標籤：context   bsp   path   wim   fun   func   this   簡單   create   

doDraw: function (path, height, width) {let that = this;var ctx = wx.createCanvasContext(‘firstCanvas‘)

 

let scale = width / height; let drawWidth = 0; // 繪製圖片的寬度 let drawHeight = 0; // 繪製圖片的高度 // 假設高度確定 if (scale >= (360/ 640)) { // 寬度過大：高度設定為1280 drawHeight = 640; drawWidth = scale * 640; let left = (drawWidth - 360) / 2; // 左邊位移量 ctx.drawImage(path, -left, 0, drawWidth, drawHeight); } else { // 寬度過小：寬度設定為720 drawWidth = 360; drawHeight = 360 / scale; let top = (drawHeight - 640) / 2; // 頂部位移量 ctx.drawImage(path, 0, -top, drawWidth, drawHeight); } //模板

 

// 繪製前景圖 ctx.drawImage(that.data.path, 72 / 2, 128 / 2, 576 / 2, 1024 / 2);

 

ctx.draw();

 

setTimeout(function () { that.doCanvas(); }, 300) },

手機適應螢幕簡單圖片處理演算法