Add html to pdf platform conversion

@@ -28,6 +28,7 @@ printing/android/local.properties
 printing/*.log
 printing/ios/Flutter
 printing/ios/Runner
+printing/android/.gradle
 
 .pana
 pedantic_analyis_options_*.yaml

+## 2.1.0
+
+* Add html to pdf platform conversion
+
 ## 2.0.4
 
 * Update Readme

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * 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 android.print;
+
+import android.app.Activity;
+import android.os.CancellationSignal;
+import android.os.ParcelFileDescriptor;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class PdfConvert {
+    public static void print(final Activity activity, final PrintDocumentAdapter adapter,
+            final PrintAttributes attributes, final Result result) {
+        adapter.onLayout(null, attributes, null, new PrintDocumentAdapter.LayoutResultCallback() {
+            @Override
+            public void onLayoutFinished(PrintDocumentInfo info, boolean changed) {
+                File outputDir = activity.getCacheDir();
+                File outputFile = null;
+                try {
+                    outputFile = File.createTempFile("printing", "pdf", outputDir);
+                } catch (IOException e) {
+                    outputFile.delete();
+                    result.onError(e.getMessage());
+                    return;
+                }
+
+                try {
+                    final File finalOutputFile = outputFile;
+                    adapter.onWrite(new PageRange[] {PageRange.ALL_PAGES},
+                            ParcelFileDescriptor.open(
+                                    outputFile, ParcelFileDescriptor.MODE_READ_WRITE),
+                            new CancellationSignal(),
+                            new PrintDocumentAdapter.WriteResultCallback() {
+                                @Override
+                                public void onWriteFinished(PageRange[] pages) {
+                                    super.onWriteFinished(pages);
+
+                                    if (pages.length == 0) {
+                                        finalOutputFile.delete();
+                                        result.onError("No page created");
+                                    }
+
+                                    result.onSuccess(finalOutputFile);
+                                    finalOutputFile.delete();
+                                }
+                            });
+                } catch (FileNotFoundException e) {
+                    outputFile.delete();
+                    result.onError(e.getMessage());
+                }
+            }
+        }, null);
+    }
+
+    public static byte[] readFile(File file) throws IOException {
+        byte[] buffer = new byte[(int) file.length()];
+        InputStream ios = null;
+        try {
+            ios = new FileInputStream(file);
+            if (ios.read(buffer) == -1) {
+                throw new IOException("EOF reached while trying to read the whole file");
+            }
+        } finally {
+            try {
+                if (ios != null) ios.close();
+            } catch (IOException e) {
+            }
+        }
+        return buffer;
+    }
+
+    public interface Result {
+        void onSuccess(File file);
+
+        void onError(String message);
+    }
+}

@@ -16,22 +16,24 @@
 
 package net.nfet.flutter.printing;
 
-import static java.lang.StrictMath.max;
-
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.CancellationSignal;
 import android.os.Environment;
 import android.os.ParcelFileDescriptor;
 import android.print.PageRange;
+import android.print.PdfConvert;
 import android.print.PrintAttributes;
 import android.print.PrintDocumentAdapter;
 import android.print.PrintDocumentInfo;
 import android.print.PrintManager;
 import android.print.pdf.PrintedPdfDocument;
+import android.webkit.WebView;
+import android.webkit.WebViewClient;
 import androidx.core.content.FileProvider;
 
 import java.io.File;
@@ -155,6 +157,28 @@ public class PrintingPlugin extends PrintDocumentAdapter implements MethodCallHa
                 sharePdf((byte[]) call.argument("doc"), (String) call.argument("name"));
                 result.success(0);
                 break;
+            case "convertHtml":
+                double width = (double) call.argument("width");
+                double height = (double) call.argument("height");
+                double marginLeft = (double) call.argument("marginLeft");
+                double marginTop = (double) call.argument("marginTop");
+                double marginRight = (double) call.argument("marginRight");
+                double marginBottom = (double) call.argument("marginBottom");
+
+                PrintAttributes.Margins margins =
+                        new PrintAttributes.Margins(Double.valueOf(marginLeft * 1000.0).intValue(),
+                                Double.valueOf(marginTop * 1000.0 / 72.0).intValue(),
+                                Double.valueOf(marginRight * 1000.0 / 72.0).intValue(),
+                                Double.valueOf(marginBottom * 1000.0 / 72.0).intValue());
+
+                PrintAttributes.MediaSize size = new PrintAttributes.MediaSize("flutter_printing",
+                        "Provided size", Double.valueOf(width * 1000.0 / 72.0).intValue(),
+                        Double.valueOf(height * 1000.0 / 72.0).intValue());
+
+                convertHtml((String) call.argument("html"), size, margins,
+                        (String) call.argument("baseUrl"));
+                result.success(0);
+                break;
             default:
                 result.notImplemented();
                 break;
@@ -192,4 +216,49 @@ public class PrintingPlugin extends PrintDocumentAdapter implements MethodCallHa
             e.printStackTrace();
         }
     }
+
+    private void convertHtml(String data, final PrintAttributes.MediaSize size,
+            final PrintAttributes.Margins margins, String baseUrl) {
+        final WebView webView = new WebView(activity.getApplicationContext());
+
+        webView.loadDataWithBaseURL(baseUrl, data, "text/HTML", "UTF-8", null);
+
+        webView.setWebViewClient(new WebViewClient() {
+            @Override
+            public void onPageFinished(WebView view, String url) {
+                super.onPageFinished(view, url);
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+                    PrintAttributes attributes =
+                            new PrintAttributes.Builder()
+                                    .setMediaSize(size)
+                                    .setResolution(
+                                            new PrintAttributes.Resolution("pdf", "pdf", 600, 600))
+                                    .setMinMargins(margins)
+                                    .build();
+
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+                        final PrintDocumentAdapter adapter =
+                                webView.createPrintDocumentAdapter("printing");
+
+                        PdfConvert.print(activity, adapter, attributes, new PdfConvert.Result() {
+                            @Override
+                            public void onSuccess(File file) {
+                                try {
+                                    byte[] fileContent = PdfConvert.readFile(file);
+                                    channel.invokeMethod("onHtmlRendered", fileContent);
+                                } catch (IOException e) {
+                                    onError(e.getMessage());
+                                }
+                            }
+
+                            @Override
+                            public void onError(String message) {
+                                channel.invokeMethod("onHtmlError", message);
+                            }
+                        });
+                    }
+                }
+            }
+        });
+    }
 }

+<!DOCTYPE html>
+<html>
+
+<head>
+  <style>
+    * {
+      font-family: Arial, Helvetica, sans-serif;
+    }
+
+    table,
+    th,
+    td {
+      border: 1px solid black;
+      border-collapse: collapse;
+    }
+
+    th,
+    td {
+      padding: 5px;
+    }
+  </style>
+</head>
+
+<body>
+  <h2>Html conversion</h2>
+
+  <caption>Sample HTML Table</caption>
+  <table>
+    <tr>
+      <th>Company</th>
+      <th>Contact</th>
+      <th>Country</th>
+    </tr>
+    <tr>
+      <td>Alfreds Futterkiste</td>
+      <td>Maria Anders</td>
+      <td>Germany</td>
+    </tr>
+    <tr>
+      <td>Centro comercial Moctezuma</td>
+      <td>Francisco Chang</td>
+      <td>Mexico</td>
+    </tr>
+    <tr>
+      <td>Ernst Handel</td>
+      <td>Roland Mendel</td>
+      <td>Austria</td>
+    </tr>
+    <tr>
+      <td>Island Trading</td>
+      <td>Helen Bennett</td>
+      <td>UK</td>
+    </tr>
+    <tr>
+      <td>Laughing Bacchus Winecellars</td>
+      <td>Yoshi Tannamuri</td>
+      <td>Canada</td>
+    </tr>
+    <tr>
+      <td>Magazzini Alimentari Riuniti</td>
+      <td>Giovanni Rovelli</td>
+      <td>Italy</td>
+    </tr>
+  </table>
+
+  <p>HTML links are defined with the a tag:</p>
+
+  <a href="https://github.com/DavBfr/dart_pdf">This is a link</a>
+
+  <h2>An Unordered HTML List</h2>
+
+  <ul>
+    <li>Coffee</li>
+    <li>Tea</li>
+    <li>Milk</li>
+  </ul>
+
+  <h2>An Ordered HTML List</h2>
+
+  <ol>
+    <li>Coffee</li>
+    <li>Tea</li>
+    <li>Milk</li>
+  </ol>
+
+</body>
+
+</html>

@@ -5,6 +5,7 @@ import 'dart:ui' as ui;
 
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
 import 'package:path_provider/path_provider.dart';
 
 import 'package:pdf/pdf.dart';
@@ -94,6 +95,14 @@ class MyAppState extends State<MyApp> {
     });
   }
 
+  Future<void> _printHtml() async {
+    print('Print html ...');
+    await Printing.layoutPdf(onLayout: (PdfPageFormat format) async {
+      final String html = await rootBundle.loadString('assets/example.html');
+      return await Printing.convertHtml(format: format, html: html);
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return RepaintBoundary(
@@ -117,6 +126,8 @@ class MyAppState extends State<MyApp> {
                     onPressed: _printScreen),
                 RaisedButton(
                     child: const Text('Save to file'), onPressed: _saveAsFile),
+                RaisedButton(
+                    child: const Text('Print Html'), onPressed: _printHtml),
               ],
             ),
           ),

@@ -26,3 +26,5 @@ dependency_overrides:
 
 flutter:
   uses-material-design: true
+  assets:
+    - assets/

@@ -16,10 +16,12 @@
 
 import Flutter
 import UIKit
+import WebKit
 
 public class SwiftPrintingPlugin: NSObject, FlutterPlugin, UIPrintInteractionControllerDelegate {
     private var channel: FlutterMethodChannel?
     private var renderer: PdfPrintPageRenderer?
+    private var urlObservation: NSKeyValueObservation?
 
     init(_ channel: FlutterMethodChannel?) {
         super.init()
@@ -52,6 +54,30 @@ public class SwiftPrintingPlugin: NSObject, FlutterPlugin, UIPrintInteractionCon
                 )
             }
             result(NSNumber(value: 1))
+        } else if call.method == "convertHtml" {
+            let width = CGFloat((args["width"] as? NSNumber)?.floatValue ?? 0.0)
+            let height = CGFloat((args["height"] as? NSNumber)?.floatValue ?? 0.0)
+            let marginLeft = CGFloat((args["marginLeft"] as? NSNumber)?.floatValue ?? 0.0)
+            let marginTop = CGFloat((args["marginTop"] as? NSNumber)?.floatValue ?? 0.0)
+            let marginRight = CGFloat((args["marginRight"] as? NSNumber)?.floatValue ?? 0.0)
+            let marginBottom = CGFloat((args["marginBottom"] as? NSNumber)?.floatValue ?? 0.0)
+            convertHtml(
+                (args["html"] as? String)!,
+                withPageSize: CGRect(
+                    x: 0.0,
+                    y: 0.0,
+                    width: width,
+                    height: height
+                ),
+                andMargin: CGRect(
+                    x: marginLeft,
+                    y: marginTop,
+                    width: width - marginRight - marginLeft,
+                    height: height - marginBottom - marginTop
+                ),
+                andBaseUrl: args["baseUrl"] as? String == nil ? nil : URL(string: (args["baseUrl"] as? String)!)
+            )
+            result(NSNumber(value: 1))
         } else {
             result(FlutterMethodNotImplemented)
         }
@@ -118,4 +144,56 @@ public class SwiftPrintingPlugin: NSObject, FlutterPlugin, UIPrintInteractionCon
         }
         UIApplication.shared.keyWindow?.rootViewController?.present(activityViewController, animated: true)
     }
+
+    func convertHtml(_ data: String, withPageSize rect: CGRect, andMargin margin: CGRect, andBaseUrl baseUrl: URL?) {
+        let viewController = UIApplication.shared.delegate?.window?!.rootViewController
+        let wkWebView = WKWebView(frame: viewController!.view.bounds)
+        wkWebView.isHidden = true
+        wkWebView.tag = 100
+        viewController?.view.addSubview(wkWebView)
+        wkWebView.loadHTMLString(data, baseURL: baseUrl ?? Bundle.main.bundleURL)
+
+        urlObservation = wkWebView.observe(\.isLoading, changeHandler: { _, _ in
+            // this is workaround for issue with loading local images
+            DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
+                // assign the print formatter to the print page renderer
+                let renderer = UIPrintPageRenderer()
+                renderer.addPrintFormatter(wkWebView.viewPrintFormatter(), startingAtPageAt: 0)
+
+                // assign paperRect and printableRect values
+                renderer.setValue(rect, forKey: "paperRect")
+                renderer.setValue(margin, forKey: "printableRect")
+
+                // create pdf context and draw each page
+                let pdfData = NSMutableData()
+                UIGraphicsBeginPDFContextToData(pdfData, .zero, nil)
+
+                for i in 0 ..< renderer.numberOfPages {
+                    UIGraphicsBeginPDFPage()
+                    renderer.drawPage(at: i, in: UIGraphicsGetPDFContextBounds())
+                }
+
+                UIGraphicsEndPDFContext()
+
+                if let viewWithTag = viewController?.view.viewWithTag(wkWebView.tag) {
+                    viewWithTag.removeFromSuperview() // remove hidden webview when pdf is generated
+
+                    // clear WKWebView cache
+                    if #available(iOS 9.0, *) {
+                        WKWebsiteDataStore.default().fetchDataRecords(ofTypes: WKWebsiteDataStore.allWebsiteDataTypes()) { records in
+                            records.forEach { record in
+                                WKWebsiteDataStore.default().removeData(ofTypes: record.dataTypes, for: [record], completionHandler: {})
+                            }
+                        }
+                    }
+                }
+
+                // dispose urlObservation
+                self.urlObservation = nil
+
+                let data = FlutterStandardTypedData(bytes: pdfData as Data)
+                self.channel?.invokeMethod("onHtmlRendered", arguments: data)
+            }
+        })
+    }
 }

@@ -21,6 +21,7 @@ typedef LayoutCallback = FutureOr<List<int>> Function(PdfPageFormat format);
 mixin Printing {
   static const MethodChannel _channel = MethodChannel('printing');
   static LayoutCallback _onLayout;
+  static Completer<List<int>> _onHtmlRendered;
 
   static Future<void> _handleMethod(MethodCall call) async {
     switch (call.method) {
@@ -37,6 +38,12 @@ mixin Printing {
           'doc': Uint8List.fromList(bytes),
         };
         return await _channel.invokeMethod('writePdf', params);
+      case 'onHtmlRendered':
+        _onHtmlRendered.complete(call.arguments);
+        break;
+      case 'onHtmlError':
+        _onHtmlRendered.completeError(call.arguments);
+        break;
     }
   }
 
@@ -89,4 +96,25 @@ mixin Printing {
     };
     return await _channel.invokeMethod('sharePdf', params);
   }
+
+  static Future<List<int>> convertHtml(
+      {@required String html,
+      String baseUrl,
+      PdfPageFormat format = PdfPageFormat.a4}) async {
+    final Map<String, dynamic> params = <String, dynamic>{
+      'html': html,
+      'baseUrl': baseUrl,
+      'width': format.width,
+      'height': format.height,
+      'marginLeft': format.marginLeft,
+      'marginTop': format.marginTop,
+      'marginRight': format.marginRight,
+      'marginBottom': format.marginBottom,
+    };
+
+    _channel.setMethodCallHandler(_handleMethod);
+    _onHtmlRendered = Completer<List<int>>();
+    await _channel.invokeMethod<void>('convertHtml', params);
+    return _onHtmlRendered.future;
+  }
 }

@@ -4,7 +4,7 @@ description: Plugin that allows Flutter apps to generate and print documents to
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/printing
 repository: https://github.com/DavBfr/dart_pdf
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
-version: 2.0.4
+version: 2.1.0
 
 environment:
   sdk: ">=2.1.0 <3.0.0"