I'm new to Flutter.
What I need:
Open a photo from android temp folder and convert to bitmap.
What am I doing:
Following this tutorial: https://flutter.dev/docs/cookbook/plugins/picture-using-camera
I'm invoking the "takePicture" method in "CameraController" which
saves the photo in a temporary file;
I open the file and try to convert to bitmap:
Code:
final Image photo = Image.file(File(imagePath));
final AssetImage image = photo.image;
final Bitmap bitmap = Bitmap.fromAssetImage(image);
What happens:
local> /data/data/io.flutter.plugins.firebasemlvisionexample/cache/2019-08-19 14:14:58.720970.png.
I/flutter ( 7943): type 'FileImage' is not a subtype of type 'AssetImage'
If you use "Bitmap.fromImage(photo)", VScode displays:
The argument type 'Image (where Image is defined in.
/Users/luis/development/flutter/packages/flutter/lib/src/widgets/image.dart)'
can't be assigned to the parameter type 'Image (where Image is defined
in
/Users/luis/development/flutter/bin/cache/pkg/sky_engine/lib/ui/painting.dart)'.
Do this:
Image.asset('images/cat.png')
Images.asset
Related
In my Flutter app, I return asset (product image) name by:
class Product {
// ...
final int id;
// ...
String get assetName => '$id-0.jpg';
}
And later, I use the asset name like:
// ...
image: AssetImage(product.assetName),
// ...
Now, the problem is some of the images are *.jpg and some are *.png like:
Is there a way to tell the Flutter image loader to try to load '$id-0.jpg' and if the file doesn't exist, then try to load '$id-0.png'? Perhaps I can do that with regular expressions, but I cannot figure out how.
You can determine if an asset exists with rootBundle.load and a try-catch block. rootBundle.load will throw an exception if the asset is not found.
ByteData image;
try{
image = await rootBundle.load(assetNameHere.jpg);
}
catch(e) {
image = await rootBundle.load(assetNameHere.png);
}
I don't know the exception that this will throw on the asset not existing, so I can't tell you which error to catch on, but you can figure that out and modify your code to only do the png code on that exception type instead of everything.
With this method, since you're already forced to load the image into memory, you can store the ByteData and use MemoryImage instead of AssetImage.
I am using this https://github.com/brendan-duncan/image/wiki to try and draw text on my image my question is how do I get the image needed for the first parameter in Image.drawString() when the image I am trying to pass is the one that is captured by the camera plugin?
final path = join(
// Store the picture in the temp directory.
// Find the temp directory using the `path_provider` plugin.
(await getTemporaryDirectory()).path,
'${DateTime.now()}.png',
);
// Attempt to take a picture and log where it's been saved.
await _controller.takePicture(path);
//this doesnt work
img.Image image = Image.file(File(path))
img.drawString(image, img.arial_24, 50, 50, "Hello World");
I am getting this error:
'Image (where Image is defined in
myflutterpath/packages/flutter/lib/src/widgets/image.dart)' can't be
assigned to a variable of type 'Image (where Image is defined in
/myflutterpath/flutter/.pub-cache/hosted/pub.dartlang.org/image-2.1.4/lib/src/image.dart)'
You're assigning an Image widget from Flutter to a img.Image variable from the image package. These are completely separate data types.
To do what you want, you need to create an img.Image object. Since your image source is a PNG file(guessing based on file extension), you'll need to decode it to raw pixel data. This can be done with the PngDecoder that's already included in the image package that you have.
img.Image image = img.PngDecoder().decodeImage(await File(path).readAsBytes());
This creates an img.Image from your PNG file instead of an Image widget.
How can I convert a PDF file into an image with Flutter?
I want to print the image to an ESC/POS printer using esc_pos_printer. This package won't accept PDFImage, it needs to be a Flutter Image.
I see plenty of PHP plugins that do this but nothing for Flutter.
edit: There is an answer to another question here which shows some code to decode an image from "pdf64" but I can't figure out exactly what "pdf64" is.
I created a PDF from html using flutter_html_to_pdflike this:
Directory appDocDir = await getApplicationDocumentsDirectory();
var targetPath = appDocDir.path;
var generatedPdfFile = await FlutterHtmlToPdf.convertFromHtmlContent(
htmlContent, targetPath, targetFileName);
generatedPdfFilePath = generatedPdfFile.path;
Now I need to know how to create a Flutter Image from that PDF or the bytecode to send raw to the printer.
You can use https://pub.dev/packages/printing:
await for (var page in Printing.raster(document)) {
final image = page.asImage();
...
}
This plugin can also convert your Html to Pdf with this:
final pdf = await Printing.convertHtml(
format: PdfPageFormat.a4,
html: '<html><body><p>Hello!</p></body></html>',
));
I'm trying to do some pre-processing in my image before using Firebase MLkit. Previously, I was simply loading my image and then passing it directly like this.
File file = await FilePicker.getFile(type: FileType.IMAGE);
final FirebaseVisionImage visionImage = FirebaseVisionImage.fromFile(file);
VisionText visionText = await textRecognizer.processImage(visionImage);
But now, I wanted to do some processing on the image. I did this using Flutter's Image package like this.
import 'package:image/image.dart' as Img;
File file = await FilePicker.getFile(type: FileType.IMAGE);
Img.Image image = Img.decodeImage(file.readAsBytesSync());
var img = Img.invert(image);
Now, how do I pass this new object to FirebaseVisionImage. I see that there is this function:
FirebaseVisionImage.fromBytes(bytes, metadata)
I'm guessing I can get bytes from the above image object using img.getBytes() but I'm confused how to set the metadata.
EDIT:
I see that one can write the image to a temporary file doing
img.writeAsBytesSync(decoded.ToList());
and then use that image again using FirebaseVisionImage.fromFile() but I would really prefer not to do that.
I'm trying to use the share() method, including an image, but I'm having trouble supplying the proper path to the image. Where should I put the image file, and what is the path (putting in the default package and trying "jar:///myimage.png" didn't work), and why is this not documented clearly?
image can be stored in storage which is following path for window
C:\Users\userName.cn1
and the image can be read by using following codes
InputStream is = Storage.getInstance().createInputStream("tizbn.JPG");
EncodedImage i = EncodedImage.create(is, is.available());
Loading image from default folder
Image i =EncodedImage.create("/tizbn.png");
Loading image From Theme
EncodedImage current = (EncodedImage) fetchResourceFile().getImage("tizbn.png");
The share API works with https://www.codenameone.com/javadoc/com/codename1/io/FileSystemStorage.html[FileSystemStorage] and not with https://www.codenameone.com/javadoc/com/codename1/io/Storage.html[Storage].
You need to save the file into a file system path which is always an absolute path, we recommend using the app home to store files. There is a sample in the developer guide section on the ShareButton covering this:
Form hi = new Form("ShareButton");
ShareButton sb = new ShareButton();
sb.setText("Share Screenshot");
hi.add(sb);
Image screenshot = Image.createImage(hi.getWidth(), hi.getHeight());
hi.revalidate();
hi.setVisible(true);
hi.paintComponent(screenshot.getGraphics(), true);
String imageFile = FileSystemStorage.getInstance().getAppHomePath() + "screenshot.png";
try(OutputStream os = FileSystemStorage.getInstance().openOutputStream(imageFile)) {
ImageIO.getImageIO().save(screenshot, os, ImageIO.FORMAT_PNG, 1);
} catch(IOException err) {
Log.e(err);
}
sb.setImageToShare(imageFile, "image/png");