canvas-animation-api.kt

Canvas(modifier = modifier,
    onDraw = {
        for (item in items) {
            translate(top = item.y, left = item.x) {
                drawContext.canvas.nativeCanvas.apply {
                    when (val itemToDraw = item.itemToDraw) {
                        is CanvasPath -> {
                            scale(
                                scale = item.scale,
                                pivot = Offset(
                                    x = itemToDraw.path.getBounds().width / 2f,
                                    y = itemToDraw.path.getBounds().height / 2f
                                )
                            ) {
                                rotate(
                                    degrees = item.angle,
                                    pivot = Offset(
                                        x = itemToDraw.path.getBounds().width / 2f,
                                        y = itemToDraw.path.getBounds().height / 2f
                                    )
                                ) {
                                    drawPath(
                                        path = itemToDraw.path,
                                        color = item.color.copy(alpha = item.alpha)
                                    )
                                }
                            }
                        }
                        is CanvasText -> {
                            val textPaint = TextPaint().apply {
                                itemToDraw.paint(this)
                                color = android.graphics.Color.argb(
                                        1,
                                        (item.color.red * 255).toInt(),
                                        (item.color.green * 255).toInt(),
                                        (item.color.blue * 255).toInt()
                                    )
                                alpha = (item.alpha * 255).toInt()
                            }
                            val bounds = Rect()
                            textPaint.getTextBounds(itemToDraw.text, 0, itemToDraw.text.length, bounds)
                            scale(
                                scale = item.scale,
                                pivot = Offset(
                                    x = bounds.width() / 2f,
                                    y = bounds.height() / 2f
                                )
                            ) {
                                rotate(
                                    degrees = item.angle,
                                    pivot = Offset(
                                        x = bounds.width() / 2f,
                                        y = bounds.height() / 2f
                                    )
                                ) {
                                    drawText(
                                        itemToDraw.text,
                                        0f,
                                        bounds.height().toFloat(),
                                        textPaint
                                    )
                                }
                            }
                        }
                        is CanvasObject -> {
                            itemToDraw.objectToDraw(this@translate, item.alpha, item.angle, item.color, item.scale)
                        }
                    }
                }
            }
        }
    }
)