/*
    2023-08-29 File created by Kari Laitinen

    (c) naturalprogramming.com

    This example demonstrates
      - Canvas drawings

    This is an Android app made of this single file.

    If you want to test this app, create an Android Compose project
    with the project name DrawingDemoC and the package name shown below.

    Then, store this file to the folder where MainActivity.kt is and
    make the following change to AndroidManifest.xml:
    android:name=".DrawingDemoCActivity"

    Imports may need to be modified if a new Android/Compose version
    is used.

    Some 'warnings':
    - tab size in this file is 3 spaces
    - underscores may be used in the names invented by the programmer

*/

package drawing.democ

import android.os.Bundle
import android.view.WindowManager
import android.view.WindowMetrics
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.ui.Modifier
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.drawscope.Stroke
import androidx.compose.ui.platform.LocalConfiguration
import androidx.compose.ui.text.ExperimentalTextApi
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.drawText
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.rememberTextMeasurer
import androidx.compose.ui.unit.sp
import drawing.democ.ui.theme.DrawingDemoCTheme

class DrawingDemoCActivity : ComponentActivity()
{
   @OptIn( ExperimentalTextApi::class )
   override fun onCreate( savedInstanceState : Bundle? )
   {
      super.onCreate( savedInstanceState )

      val metrics: WindowMetrics = getSystemService(WindowManager::class.java).currentWindowMetrics

      val raw_screen_width = metrics.bounds.width()
      val raw_screen_height = metrics.bounds.height()

      setContent {
         DrawingDemoCTheme {
            // A surface container using the 'background' color from the theme
            Surface(
               modifier = Modifier.fillMaxSize(),
               color = MaterialTheme.colorScheme.background
            )
            {
               val configuration = LocalConfiguration.current

               val screen_width_dp = configuration.screenWidthDp
               val screen_height_dp = configuration.screenHeightDp

               val textMeasurer = rememberTextMeasurer()

               Canvas( modifier = Modifier.fillMaxSize() )
               {
                  //val canvasSize = size
                  val canvas_width = size.width
                  val canvas_height = size.height

                  drawText(
                     textMeasurer = textMeasurer,
                     text = "Canvas size: " + canvas_width + " x " + canvas_height,
                     topLeft = Offset( x = 20F, y = 40F ),
                     style = TextStyle(
                        fontSize = 12.sp,
                        fontWeight = FontWeight.Bold )
                  )

                  drawText(
                     textMeasurer = textMeasurer,
                     text = "Screen size (dp): " + screen_width_dp + " x " + screen_height_dp,
                     topLeft = Offset( x = 20F, y = 70F ),
                     style = TextStyle(
                        fontSize = 12.sp,
                        fontWeight = FontWeight.Bold )
                  )

                  drawText(
                     textMeasurer = textMeasurer,
                     text = "Raw screen size: " + raw_screen_width + " x " + raw_screen_height,
                     topLeft = Offset( x = 20F, y = 100F ),
                     style = TextStyle(
                        fontSize = 12.sp,
                        fontWeight = FontWeight.Bold )
                  )

                  drawLine(
                     color = Color.Green,
                     start = Offset( x = canvas_width / 6F, y = canvas_height / 8F ),
                     end = Offset( x = canvas_width * 5F / 6F, y = canvas_height / 8F ),
                     strokeWidth = 8F
                  )

                  drawRect(
                     color = Color.Cyan,
                     topLeft = Offset( x = canvas_width / 2F - canvas_height / 8F,
                                       y = canvas_height / 4F - canvas_height / 20F ),
                     size = Size(canvas_height / 4F, canvas_height / 10F )
                  )

                  // The following call draws a hollow rectangle around the Cyan rectangle,
                  // so that there is a margin of 20 pixels.
                  drawRect(
                     color = Color.Blue,
                     topLeft = Offset( x = canvas_width / 2F - canvas_height / 8F - 20,
                                       y = canvas_height / 4F - canvas_height / 20F - 20 ),
                     size = Size(canvas_height / 4F + 40, canvas_height / 10F + 40 ),
                     style = Stroke( width = 4F )
                  )

                  drawCircle(
                     color = Color.Magenta,
                     radius = canvas_height / 10F,
                     center = Offset( x = canvas_width / 2F, y = canvas_height / 2F )
                  )

                  drawCircle(
                     color = Color.Blue,
                     radius = canvas_height / 10F,
                     center = Offset( x = canvas_width / 2F, y = canvas_height / 2F ),
                     style = Stroke( 4F )
                  )

                  // The following calls draw a 'pacman'

                  drawArc(
                     color = Color.Yellow,
                     startAngle = 45F,
                     sweepAngle = 270F,
                     useCenter = true,
                     topLeft = Offset( x = canvas_width / 2F - canvas_height / 8F - 60,
                                       y = canvas_height * 22 / 32F ),
                     size = Size(canvas_height / 4F, canvas_height / 4F)
                  )

                  drawArc(
                     color = Color.Black,
                     startAngle = 45F,
                     sweepAngle = 270F,
                     useCenter = true,
                     topLeft = Offset( x = canvas_width / 2F - canvas_height / 8F - 60,
                                       y = canvas_height * 22 / 32F  ),
                     size = Size(canvas_height / 4F, canvas_height / 4F ),
                     style = Stroke( 4F )
                  )

                  // The following method calls draw a 'pie'.

                  drawArc(
                     color = Color.Yellow,
                     startAngle = 315F,
                     sweepAngle = 90F,
                     useCenter = true,
                     topLeft = Offset( x = canvas_width / 2F - canvas_height / 8F + 60,
                                       y = canvas_height * 22 / 32F ),
                     size = Size(canvas_height / 4F, canvas_height / 4F )
                  )

                  drawArc(
                     color = Color.Black,
                     startAngle = 315F,
                     sweepAngle = 90F,
                     useCenter = true,
                     topLeft = Offset( x = canvas_width / 2F - canvas_height / 8F + 60,
                                       y = canvas_height * 22 / 32F ),
                     size = Size(canvas_height / 4F, canvas_height / 4F ),
                     style = Stroke( 4F )
                  )

               }
            }
         }
      }
   }
}