PixelWriten canvas 不会在屏幕上显示

Question

我有一个与像素 RGB 值相对应的整数数组，我试图将它们写入图像，然后我将其添加到视图中显示的 canvas。我遵循了使用 pixelWriter 的 JavaFX 文档指南，我知道我向视图添加 canvas 的语法是正确的，因为我在我的应用程序的其他地方做了同样的事情，并测试了在此处放置不同的 canvas正确。

我试过上下文方式：查看 class:

vbox(20.0, Pos.BOTTOM_CENTER) {
    if (controller.t > 100) { //same results with or without this
        label("IR camera view title")
        children.add(controller.rPiSensors.canvasIR)
    }
}

型号class:

val canvasIR = Canvas(lIR_WIDTH_RES.toDouble(), lIR_HEIGHT_RES.toDouble())
val gc: GraphicsContext = canvasIR.graphicsContext2D
var lIRPixelWriter = gc.pixelWriter


for (y in 0 until  32) {
    for (x in 0 until 24) {
        lIRPixelWriter.setPixels(0,0,lIR_WIDTH_RES,lIR_HEIGHT_RES, PixelFormat.getIntArgbInstance(), lIRHeatMapPixelInts, 0 , lIR_WIDTH_RES)
     }
}

我也尝试过 SO post Creating a Javafx image from a int array:

中提到的 WritableImage 方式

查看class:

vbox(20.0, Pos.BOTTOM_CENTER) {
    if (controller.t > 100) { //same results with or without this
        label("IR camera view title")
        //tested this too controller.rPiSensors.imageView.show()
        children.add(controller.rPiSensors.imageView)
    }
}

型号class:

var lIRHeatMapPixelInts = IntArray(768) //24*32
//write to this in calculateIRPixelHelper below

var lIRHeatImage = WritableImage(lIR_WIDTH_RES, lIR_HEIGHT_RES)
var lIRPixelWriter = lIRHeatImage.pixelWriter
val imageView = ImageView(lIRHeatImage)

for (y in 0 until  32) {
    for (x in 0 until 24) {
        lIRPixelWriter.setPixels(0,0,lIR_WIDTH_RES,lIR_HEIGHT_RES, PixelFormat.getIntArgbInstance(), lIRHeatMapPixelInts, 0 , lIR_WIDTH_RES)
     }
}

从温度的浮点值获取 IR RGBInt 的函数（显示在获取数据的 RasPi 上是正确的，并且我已经将接收到的数据与 snet RasPi 数据进行了比较）

fun calculateIRPixelHelper(x : Int, y : Int, v : Float) {
    //float color[NUM_COLORS][3] = { {0;0;0}; {0;0;1}; {0;1;0}; {1,1,0},{1,0,0}, {1,0,1}, {1,1,1} }
    val color : Array<FloatArray> = arrayOf(floatArrayOf(0.0f,0.0f,0.0f), floatArrayOf(0.0f,0.0f,1.0f), floatArrayOf(0.0f,1.0f,0.0f), floatArrayOf(1.0f,1.0f,0.0f), floatArrayOf(1.0f,0.0f,0.0f), floatArrayOf(1.0f,0.0f,1.0f), floatArrayOf(1.0f,1.0f,1.0f))
    var outputV = v
    val idx1 : Int
    val idx2 : Int
    var fractBetween = 0.0f
    val vmin = 5.0f
    val vmax = 50.0f
    val vrange = vmax-vmin
    outputV -= vmin
    outputV /= vrange
    val ir : Int
    val ig : Int
    val ib : Int
    val pixelRGBInt : Int
    if (outputV <= 0) {
        idx1= 0
        idx2= 0
    } else if (outputV >= 1) {
        idx1 = (NUM_COLORS-1)
        idx2 = (NUM_COLORS-1)
    } else {
        outputV *= (NUM_COLORS-1)
        idx1 = truncate(outputV).toInt()
        idx2 = idx1+1
        fractBetween = outputV - idx1
    }

    ir = ((((color[idx2][0] - color[idx1][0]) * fractBetween) + color[idx1][0]) * 255.0).toInt()
    ig = ((((color[idx2][1] - color[idx1][1]) * fractBetween) + color[idx1][1]) * 255.0).toInt()
    ib = ((((color[idx2][2] - color[idx1][2]) * fractBetween) + color[idx1] [2]) * 255.0).toInt()
    pixelRGBInt = (ir shl 16) or (ig shl 8) or ib


    for(py  in 0 until IMAGE_SCALE) {
        for(px in 0 until IMAGE_SCALE) {
            lIRHeatMapPixelInts[x + px + IMAGE_SCALE*(y + py)] = pixelRGBInt
        }
    }
}

Here are the float values of the temperature

the pixel ints, which are all 0 beyond the first ~50

And part of the list of values saved in the canvas

对于第一种方法，canvas 中写入了 133K 脏位，当我使用调试器时，似乎 PixelWriter.setPixels 几乎在每次调用时都在写入位，但在增加中缓慢进展值（趋势是这样的：写 val pos = 12, 30, 62, 12, 30, 62, 78, 99, 10 ... 如果怀疑这是问题所在，我可以抄下确切的数字）

在这两种情况下，我认为问题出在 canvas 填充后更新，但我已经消除了这个理论，只在模型中设置了标志后才添加 canvas -- 仍然除了 canvas.

的标题外，什么也没有出现

我花了大约一整天的时间来尝试展示这个，我们将不胜感激 :)

Answer 1

Alpha 位设置为零，对于非透明像素，必须将它们在 pixelRGBint 高位设置为 non-zero！

PixelWriten canvas 不会在屏幕上显示

PixelWriten canvas won't display on screen

javafx

canvas

pixel

tornadofx