| /* |
| * Copyright 2020 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.compose.ui.graphics.samples |
| |
| import androidx.annotation.Sampled |
| import androidx.compose.Composable |
| import androidx.ui.core.Modifier |
| import androidx.compose.foundation.Canvas |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.ui.graphics.drawscope.inset |
| import androidx.compose.ui.graphics.drawscope.rotate |
| import androidx.compose.ui.graphics.drawscope.withTransform |
| import androidx.compose.foundation.layout.preferredSize |
| import androidx.ui.unit.dp |
| |
| /** |
| * Sample showing how to use CanvasScope to issue drawing commands into |
| * a given canvas as well as providing transformations to the drawing environment |
| */ |
| @Sampled |
| @Composable |
| fun DrawScopeSample() { |
| // Sample showing how to use the DrawScope receiver scope to issue |
| // drawing commands |
| Canvas(Modifier.preferredSize(120.dp)) { |
| drawRect(color = Color.Gray) // Draw grey background |
| // Inset content by 10 pixels on the left/right sides and 12 by the |
| // top/bottom |
| inset(10.0f, 12.0f) { |
| val quadrantSize = size / 2.0f |
| |
| // Draw a rectangle within the inset bounds |
| drawRect( |
| size = quadrantSize, |
| color = Color.Red |
| ) |
| |
| rotate(45.0f) { |
| drawRect(size = quadrantSize, color = Color.Blue) |
| } |
| } |
| } |
| } |
| |
| @Sampled |
| @Composable |
| fun DrawScopeBatchedTransformSample() { |
| Canvas(Modifier.preferredSize(120.dp)) { // CanvasScope |
| inset(20.0f) { |
| // Use withTransform to batch multiple transformations for 1 or more drawing calls |
| // that are to be drawn. |
| // This is more efficient than issuing nested translation, rotation and scaling |
| // calls as the internal state is saved once before and after instead of multiple |
| // times between each transformation if done individually |
| withTransform({ |
| translate(10.0f, 12.0f) |
| rotate(45.0f) |
| scale(2.0f, 0.5f) |
| }) { |
| drawRect(Color.Cyan) |
| drawCircle(Color.Blue) |
| } |
| drawRect(Color.Red, alpha = 0.25f) |
| } |
| } |
| } |