Steyn Geldenhuys
4769b2f8e9
|
4 years ago | |
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.. | ||
README.md | 4 years ago | |
compose-logo.xml | 4 years ago | |
draw_image_into_canvas.png | ||
image_from_resources.png | ||
loading_svg_images.png | 4 years ago | |
loading_xml_vector_images.png | 4 years ago | |
sample.png | ||
tray_icon.png | ||
window_icon.png |
README.md
Image and in-app icons manipulations
What is covered
In this tutorial we will show you how to work with images using Compose for Desktop.
Loading images from resources
Using images from application resources is very simple. Suppose we have a PNG image that is placed in the resources/images
directory in our project. For this tutorial we will use the image sample:
import androidx.compose.desktop.Window
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.ui.Modifier
import androidx.compose.ui.res.imageResource
fun main() {
Window {
Image(
bitmap = imageResource("images/sample.png"), // ImageBitmap
contentDescription = "Sample",
modifier = Modifier.fillMaxSize()
)
}
}
Loading images from device storage
To create an ImageBitmap
from a loaded image stored in the device memory you can use org.jetbrains.skija.Image
:
import androidx.compose.desktop.Window
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.graphics.asImageBitmap
import org.jetbrains.skija.Image
import java.io.File
fun main() {
Window {
val image = remember { imageFromFile(File("sample.png")) }
Image(
bitmap = image,
contentDescription = "Sample",
modifier = Modifier.fillMaxSize()
)
}
}
fun imageFromFile(file: File): ImageBitmap {
return Image.makeFromEncoded(file.readBytes()).asImageBitmap()
}
Drawing raw image data using native canvas
You may want to draw raw image data, in which case you can use Canvas
and drawIntoCanvas
.
import androidx.compose.desktop.Window
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
import androidx.compose.ui.graphics.nativeCanvas
import org.jetbrains.skija.Bitmap
import org.jetbrains.skija.ColorAlphaType
import org.jetbrains.skija.IRect
import org.jetbrains.skija.ImageInfo
import java.awt.image.BufferedImage
import java.io.File
import javax.imageio.ImageIO
fun main() {
Window {
val bitmap = remember { bitmapFromByteArray() }
Canvas(
modifier = Modifier.fillMaxSize()
) {
drawIntoCanvas { canvas ->
canvas.nativeCanvas.drawBitmapRect(
bitmap,
IRect(0, 0, bitmap.getWidth(), bitmap.getHeight()).toRect()
)
}
}
}
}
fun bitmapFromByteArray(): Bitmap {
var image: BufferedImage? = null
try {
image = ImageIO.read(File("sample.png"))
} catch (e: Exception) {
// image file does not exist
}
if (image == null) {
image = BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB)
}
val pixels = getBytes(image) // assume we only have raw pixels
// allocate and fill skija Bitmap
val bitmap = Bitmap()
bitmap.allocPixels(ImageInfo.makeS32(image.width, image.height, ColorAlphaType.PREMUL))
bitmap.installPixels(bitmap.getImageInfo(), pixels, (image.width * 4).toLong())
return bitmap
}
// creating byte array from BufferedImage
private fun getBytes(image: BufferedImage): ByteArray {
val width = image.width
val height = image.height
val buffer = IntArray(width * height)
image.getRGB(0, 0, width, height, buffer, 0, width)
val pixels = ByteArray(width * height * 4)
var index = 0
for (y in 0 until height) {
for (x in 0 until width) {
val pixel = buffer[y * width + x]
pixels[index++] = ((pixel and 0xFF)).toByte() // Blue component
pixels[index++] = (((pixel shr 8) and 0xFF)).toByte() // Green component
pixels[index++] = (((pixel shr 16) and 0xFF)).toByte() // Red component
pixels[index++] = (((pixel shr 24) and 0xFF)).toByte() // Alpha component
}
}
return pixels
}
Setting the application window icon
You have 2 ways to set icon for window:
- Via parameter in
Window
function (or inAppWindow
constructor)
import androidx.compose.desktop.Window
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.graphics.asImageBitmap
import org.jetbrains.skija.Image
import java.awt.image.BufferedImage
import java.io.ByteArrayOutputStream
import java.io.File
import javax.imageio.ImageIO
fun main() {
val image = getWindowIcon()
Window(
icon = image
) {
val imageAsset = remember { asImageAsset(image) }
Image(
bitmap = imageAsset,
contentDescription = "Icon",
modifier = Modifier.fillMaxSize()
)
}
}
fun getWindowIcon(): BufferedImage {
var image: BufferedImage? = null
try {
image = ImageIO.read(File("sample.png"))
} catch (e: Exception) {
// image file does not exist
}
if (image == null) {
image = BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB)
}
return image
}
fun asImageAsset(image: BufferedImage): ImageBitmap {
val baos = ByteArrayOutputStream()
ImageIO.write(image, "png", baos)
return Image.makeFromEncoded(baos.toByteArray()).asImageBitmap()
}
- Using
setIcon()
method
import androidx.compose.desktop.AppManager
import androidx.compose.desktop.Window
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.graphics.asImageBitmap
import org.jetbrains.skija.Image
import java.awt.image.BufferedImage
import java.io.ByteArrayOutputStream
import java.io.File
import javax.imageio.ImageIO
fun main() {
val image = getWindowIcon()
Window {
val imageAsset = remember { asImageAsset(image) }
Image(
bitmap = imageAsset,
contentDescription = "Icon",
modifier = Modifier.fillMaxSize()
)
}
AppManager.focusedWindow?.setIcon(image)
}
fun getWindowIcon(): BufferedImage {
var image: BufferedImage? = null
try {
image = ImageIO.read(File("sample.png"))
} catch (e: Exception) {
// image file does not exist
}
if (image == null) {
image = BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB)
}
return image
}
fun asImageAsset(image: BufferedImage): ImageBitmap {
val baos = ByteArrayOutputStream()
ImageIO.write(image, "png", baos)
return Image.makeFromEncoded(baos.toByteArray()).asImageBitmap()
}
Setting the application tray icon
You can create a tray icon for your application:
import androidx.compose.desktop.AppManager
import androidx.compose.desktop.Window
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.runtime.DisposableEffect
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.graphics.asImageBitmap
import androidx.compose.ui.window.MenuItem
import androidx.compose.ui.window.Tray
import org.jetbrains.skija.Image
import java.awt.image.BufferedImage
import java.io.ByteArrayOutputStream
import java.io.File
import javax.imageio.ImageIO
fun main() {
val image = getWindowIcon()
Window {
DisposableEffect(Unit) {
val tray = Tray().apply {
icon(getWindowIcon())
menu(
MenuItem(
name = "Quit App",
onClick = { AppManager.exit() }
)
)
}
onDispose {
tray.remove()
}
}
val imageAsset = asImageAsset(image)
Image(
bitmap = imageAsset,
contentDescription = "Icon",
modifier = Modifier.fillMaxSize()
)
}
val current = AppManager.focusedWindow
if (current != null) {
current.setIcon(image)
}
}
fun getWindowIcon(): BufferedImage {
var image: BufferedImage? = null
try {
image = ImageIO.read(File("sample.png"))
} catch (e: Exception) {
// image file does not exist
}
if (image == null) {
image = BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB)
}
return image
}
fun asImageAsset(image: BufferedImage): ImageBitmap {
val baos = ByteArrayOutputStream()
ImageIO.write(image, "png", baos)
return Image.makeFromEncoded(baos.toByteArray()).asImageBitmap()
}
Loading SVG images
Suppose we have an SVG image placed in the resources/images
directory in our project.
import androidx.compose.desktop.Window
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.ui.Modifier
import androidx.compose.ui.res.svgResource
fun main() {
Window {
Image(
painter = svgResource("images/idea-logo.svg"),
contentDescription = "Idea logo",
modifier = Modifier.fillMaxSize()
)
}
}
Loading XML vector images
Compose for Desktop supports XML vector images. XML vector images come from the world of Android. We implemented it on the desktop so we can use common resources in a cross-platform application.
SVG files can be converted to XML with Android Studio or with third-party tools.
Suppose we have an XML image placed in the resources/images
directory in our project.
import androidx.compose.desktop.Window
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.ui.Modifier
import androidx.compose.ui.res.vectorXmlResource
fun main() {
Window {
Image(
imageVector = vectorXmlResource("images/compose-logo.xml"),
contentDescription = "Compose logo",
modifier = Modifier.fillMaxSize()
)
}
}