如何使用jsPsych心理物理学插件中的“手动”属性调用函数来绘制刺激？

Question

我一直试图使用“手动”对象属性来绘制光栅刺激。我用drawFunc编写了一个函数来绘制刺激图。但是，我希望在每次试验中使用context.filter更改一个输入参数，即对比度级别。我想在刺激变量之外定义函数和输入参数，并通过提供相关参数调用绘制补丁的函数。然而，这似乎行不通。每次我都不得不定义函数。有办法解决这个问题吗？

var Left0 = {
    obj_type: 'manual', // means a rectangle
    startX: 550, // location in the canvas
    startY: 325,
    endX: 700,
    endY: 325,
    width: 300, // of the rectangle
    height: 200,
    horiz_pix_sec: 30,
    show_start_time: 0,
    motion_start_time: 2000,
    drawFunc() {
        context = jsPsych.currentTrial().context;
        var pos = 0;
        const gradLength = 100;
        const my_gradient  = context.createLinearGradient(400, 0, 600, 0);
        const bands = 10;
        const colors = ["#000", "#FFF"];
        const stops = bands * colors.length;
        while (pos <= stops) {
            my_gradient.addColorStop(pos / stops, colors[pos % colors.length]);
            pos++;
        }
        context.filter = 'contrast('+ CL1 +')';
        context.fillStyle = my_gradient;
        context.fillRect(500,325,gradLength,gradLength);
        context.stroke();
    }
};

//相反，我只想像这样定义函数一次。

function drawFunc (x1, y1, x2, y2, CL1, x,y) {
    context = jsPsych.currentTrial().context;
    var pos = 0;
    const gradLength = 100;
    const my_gradient  = context.createLinearGradient(x1, y1, x2, y2);
    const bands = 10;
    const colors = ["#000", "#FFF"];
    const stops = bands * colors.length;
    while (pos <= stops) {
        my_gradient.addColorStop(pos / stops, colors[pos % colors.length]);
        pos++;
    }
    context.filter = 'contrast('+ CL1 +')';
    context.fillStyle = my_gradient;
    context.fillRect(x,y,gradLength,gradLength);
    context.stroke();
}

//然后稍后再调用它

var Left0 = {
    obj_type: 'manual', // means a rectangle
    startX: 550, // location in the canvas
    startY: 325,
    endX: 700,
    endY: 325,
    width: 300, // of the rectangle
    height: 200,
    horiz_pix_sec: 30,
    show_start_time: 0,
    motion_start_time: 2000,
    drawFunc: drawFunc(400, 0, 600, 0, 0.5, 500, 325)
} 

请帮助解决这个问题。

Answer 1

您可以将drawFunc(...)包装在匿名函数中：

var Left0 = {
    obj_type: 'manual', // means a rectangle
    startX: 550, // location in the canvas
    startY: 325,
    endX: 700,
    endY: 325,
    width: 300, // of the rectangle
    height: 200,
    horiz_pix_sec: 30,
    show_start_time: 0,
    motion_start_time: 2000,
    drawFunc: function(){
        drawFunc(400, 0, 600, 0, 0.5, 500, 325)
    }
}

这是因为drawFunc参数需要一个函数。如果使用drawFunc(...)而不将其包装在匿名函数中，则该参数是函数的返回值，而不是函数本身。