你好，为什么我用canvasToTempFilePath生成图片编辑器里是可以显示图片的，但是手机里测试不现实图片，只显示文字？


var textX = that.data.textX,
textY = that.data.textY + that.data.textSize/2;
ctx.drawImage(that.data.picPath, that.data.upImgX - that.data.imgx, that.data.upImgY - that.data.imgy, that.data.upImgWidth, that.data.upImgHeight);//图片
ctx.save();
ctx.translate(textX, textY);//设置画布上的(0,0)位置，也就是旋转的中心点
ctx.rotate(that.data.textRotate * Math.PI / 180);
ctx.setFillStyle('#' + that.data.color[that.data.colorUsed]);
ctx.setFontSize((that.data.textSize / 2) * that.data.screenRatio);
ctx.fillText(that.data.textCon, 0, 0);
ctx.restore();


ctx.draw(false, function (e) {
setTimeout(function(){
wx.canvasToTempFilePath({ //生成图片
canvasId: 'myCanvas',
success: function (res) {
that.setData({
imagePath: res.tempFilePath
})
console.log(res.tempFilePath);
wx.navigateTo({
url: "/pages/games/singleShare/singleShare?imagePath=" + res.tempFilePath
})
},
fail: function (res) {
console.log(res)
}
},this)
},500)
});