Improve PdfPreview memory consumption

@@ -4,6 +4,7 @@
 
 
 - iOS: Set cutLength to be currentSize.height [Liam Downey]
 - iOS: Set cutLength to be currentSize.height [Liam Downey]
 - Add Flutter 3 warning workaround
 - Add Flutter 3 warning workaround
+- Improve PdfPreview memory consumption
 
 
 ## 5.9.0
 ## 5.9.0
 
 

@@ -16,20 +16,24 @@
 
 
 import 'package:flutter/material.dart';
 import 'package:flutter/material.dart';
 
 
-import '../raster.dart';
-
 /// Represents one PDF page
 /// Represents one PDF page
 class PdfPreviewPage extends StatelessWidget {
 class PdfPreviewPage extends StatelessWidget {
   /// Create a PDF page widget
   /// Create a PDF page widget
   const PdfPreviewPage({
   const PdfPreviewPage({
     Key? key,
     Key? key,
-    this.page,
+    required this.image,
+    required this.width,
+    required this.height,
     this.pdfPreviewPageDecoration,
     this.pdfPreviewPageDecoration,
     this.pageMargin,
     this.pageMargin,
   }) : super(key: key);
   }) : super(key: key);
 
 
   /// Image representing the content of the page
   /// Image representing the content of the page
-  final PdfRaster? page;
+  final ImageProvider image;
+
+  final int width;
+
+  final int height;
 
 
   /// Decoration around the page
   /// Decoration around the page
   final Decoration? pdfPreviewPageDecoration;
   final Decoration? pdfPreviewPageDecoration;
@@ -39,7 +43,6 @@ class PdfPreviewPage extends StatelessWidget {
 
 
   @override
   @override
   Widget build(BuildContext context) {
   Widget build(BuildContext context) {
-    final im = PdfRasterImage(page!);
     final scrollbarTrack = Theme.of(context)
     final scrollbarTrack = Theme.of(context)
             .scrollbarTheme
             .scrollbarTheme
             .thickness
             .thickness
@@ -66,9 +69,9 @@ class PdfPreviewPage extends StatelessWidget {
             ],
             ],
           ),
           ),
       child: AspectRatio(
       child: AspectRatio(
-        aspectRatio: page!.width / page!.height,
+        aspectRatio: width / height,
         child: Image(
         child: Image(
-          image: im,
+          image: image,
           fit: BoxFit.cover,
           fit: BoxFit.cover,
         ),
         ),
       ),
       ),

@@ -183,8 +183,8 @@ class _PdfPreviewState extends State<PdfPreview> {
 
 
     if (!widget.canChangePageFormat && pages.isNotEmpty) {
     if (!widget.canChangePageFormat && pages.isNotEmpty) {
       format = PdfPageFormat(
       format = PdfPageFormat(
-        pages.first.page!.width * PdfPageFormat.inch / dpi,
-        pages.first.page!.height * PdfPageFormat.inch / dpi,
+        pages.first.width * PdfPageFormat.inch / dpi,
+        pages.first.height * PdfPageFormat.inch / dpi,
         marginAll: 5 * PdfPageFormat.mm,
         marginAll: 5 * PdfPageFormat.mm,
       );
       );
     }
     }

@@ -37,7 +37,7 @@ mixin PdfPreviewRaster on State<PdfPreviewCustom> {
   PdfPageFormat get pageFormat => widget.pageFormat;
   PdfPageFormat get pageFormat => widget.pageFormat;
 
 
   /// Resulting pages
   /// Resulting pages
-  final List<PdfPreviewPage> pages = <PdfPreviewPage>[];
+  final pages = <PdfPreviewPage>[];
 
 
   /// Printing subsystem information
   /// Printing subsystem information
   PrintingInfo? info;
   PrintingInfo? info;
@@ -57,6 +57,10 @@ mixin PdfPreviewRaster on State<PdfPreviewCustom> {
   @override
   @override
   void dispose() {
   void dispose() {
     _previewUpdate?.cancel();
     _previewUpdate?.cancel();
+    for (final e in pages) {
+      e.image.evict();
+    }
+    pages.clear();
     super.dispose();
     super.dispose();
   }
   }
 
 
@@ -159,26 +163,35 @@ mixin PdfPreviewRaster on State<PdfPreviewCustom> {
           _rastering = false;
           _rastering = false;
           return;
           return;
         }
         }
-        setState(() {
-          if (pages.length <= pageNum) {
-            pages.add(PdfPreviewPage(
-              page: page,
-              pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
-              pageMargin: widget.previewPageMargin,
-            ));
-          } else {
-            pages[pageNum] = PdfPreviewPage(
-              page: page,
-              pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
-              pageMargin: widget.previewPageMargin,
-            );
-          }
-        });
+
+        if (pages.length <= pageNum) {
+          pages.add(PdfPreviewPage(
+            image: MemoryImage(await page.toPng()),
+            width: page.width,
+            height: page.height,
+            pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
+            pageMargin: widget.previewPageMargin,
+          ));
+        } else {
+          pages[pageNum].image.evict();
+          pages[pageNum] = PdfPreviewPage(
+            image: MemoryImage(await page.toPng()),
+            width: page.width,
+            height: page.height,
+            pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
+            pageMargin: widget.previewPageMargin,
+          );
+        }
+        setState(() {});
 
 
         pageNum++;
         pageNum++;
       }
       }
 
 
+      for (var index = pageNum; index < pages.length; index++) {
+        pages[index].image.evict();
+      }
       pages.removeRange(pageNum, pages.length);
       pages.removeRange(pageNum, pages.length);
+      setState(() {});
     } catch (exception, stack) {
     } catch (exception, stack) {
       InformationCollector? collector;
       InformationCollector? collector;