MyView.kt

package com.example.ui.component

import androidx.compose.foundation.*
import androidx.compose.foundation.interaction.MutableInteractionSource
import androidx.compose.foundation.layout.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.focus.FocusRequester
import androidx.compose.ui.focus.focusRequester
import androidx.compose.ui.focus.focusTarget
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.graphics.*
import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
import androidx.compose.ui.input.key.isCtrlPressed
import androidx.compose.ui.input.key.onKeyEvent
import androidx.compose.ui.input.mouse.MouseScrollOrientation
import androidx.compose.ui.input.mouse.MouseScrollUnit
import androidx.compose.ui.input.mouse.mouseScrollFilter
import androidx.compose.ui.input.pointer.pointerMoveFilter
import androidx.compose.ui.unit.dp
import com.riskrieg.editor.model.EditorModel
import java.awt.Point
import kotlin.math.abs

@OptIn(ExperimentalFoundationApi::class, androidx.compose.ui.ExperimentalComposeUiApi::class)
@Composable
fun MyView(model: EditorModel, viewModifier: Modifier) {
    val stateVertical = rememberScrollState(0)
    val stateHorizontal = rememberScrollState(0)

    var scale: Float by remember { mutableStateOf(1.0f) }

    var canZoom: Boolean by remember { mutableStateOf(false) }

    Box(modifier = viewModifier.background(color = Color(255, 255, 255))) {
        Box(
            modifier = Modifier
                .fillMaxSize()
                .verticalScroll(stateVertical) // tried enabled = false, doesn't seem to do anything
                .horizontalScroll(stateHorizontal)
        ) {
            Canvas(modifier = Modifier
                .width((model.image().width * scale).dp)
                .height((model.image().height * scale).dp)
                .align(Alignment.Center)
                .onKeyEvent { keyEvent ->
                    canZoom = keyEvent.isCtrlPressed
                    false
                }
                .mouseScrollFilter(onMouseScroll = { event, _ ->
                    if (event.orientation == MouseScrollOrientation.Vertical && canZoom) {
                        val deltaY = when (val delta = event.delta) {
                            is MouseScrollUnit.Line -> -delta.value
                            is MouseScrollUnit.Page -> -delta.value
                        }
                        scale *= 1.01.pow(deltaY.toDouble()).toFloat()
                    }
                    false
                })
            ) {
                drawIntoCanvas { canvas -> // drawing shapes and stuff
                    canvas.scale(scale, scale, 0f, 0f)
                }
            }
        }
        VerticalScrollbar(
            modifier = Modifier.fillMaxHeight().align(Alignment.CenterEnd),
            adapter = rememberScrollbarAdapter(stateVertical)
        )
        HorizontalScrollbar(
            modifier = Modifier.fillMaxWidth().align(Alignment.BottomCenter).padding(end = 12.dp),
            adapter = rememberScrollbarAdapter(stateHorizontal)
        )
    }

}