Fix some null-safety issues

@@ -123,7 +123,7 @@ abstract class PdfAnnotBase {
   /// Color
   final PdfColor? color;
 
-  final Map<String, PdfDataType> _appearances = <String, PdfDataType>{};
+  final _appearances = <String, PdfDataType>{};
 
   PdfName? _as;
 
@@ -171,19 +171,13 @@ abstract class PdfAnnotBase {
     }
 
     if (matrix != null) {
-      s.params['/Matrix'] = PdfArray.fromNum(<double>[
-        matrix[0],
-        matrix[1],
-        matrix[4],
-        matrix[5],
-        matrix[12],
-        matrix[13]
-      ]);
+      s.params['/Matrix'] = PdfArray.fromNum(
+          [matrix[0], matrix[1], matrix[4], matrix[5], matrix[12], matrix[13]]);
     }
 
     final bbox = boundingBox ?? PdfRect.fromPoints(PdfPoint.zero, rect.size);
     s.params['/BBox'] =
-        PdfArray.fromNum(<double?>[bbox.x, bbox.y, bbox.width, bbox.height]);
+        PdfArray.fromNum([bbox.x, bbox.y, bbox.width, bbox.height]);
     final g = PdfGraphics(s, s.buf);
 
     if (selected && name != null) {
@@ -196,14 +190,14 @@ abstract class PdfAnnotBase {
   @mustCallSuper
   void build(PdfPage page, PdfObject object, PdfDict params) {
     params['/Subtype'] = PdfName(subtype);
-    params['/Rect'] = PdfArray.fromNum(
-        <double?>[rect.left, rect.bottom, rect.right, rect.top]);
+    params['/Rect'] =
+        PdfArray.fromNum([rect.left, rect.bottom, rect.right, rect.top]);
 
     params['/P'] = page.ref();
 
     // handle the border
     if (border == null) {
-      params['/Border'] = PdfArray.fromNum(const <int>[0, 0, 0]);
+      params['/Border'] = PdfArray.fromNum(const [0, 0, 0]);
     } else {
       params['/BS'] = border!.ref();
     }
@@ -283,7 +277,7 @@ class PdfAnnotNamedLink extends PdfAnnotBase {
   void build(PdfPage page, PdfObject object, PdfDict params) {
     super.build(page, object, params);
     params['/A'] = PdfDict(
-      <String, PdfDataType>{
+      {
         '/S': const PdfName('/GoTo'),
         '/D': PdfSecString.fromString(object, dest),
       },
@@ -315,7 +309,7 @@ class PdfAnnotUrlLink extends PdfAnnotBase {
   void build(PdfPage page, PdfObject object, PdfDict params) {
     super.build(page, object, params);
     params['/A'] = PdfDict(
-      <String, PdfDataType>{
+      {
         '/S': const PdfName('/URI'),
         '/URI': PdfSecString.fromString(object, url),
       },

@@ -115,7 +115,7 @@ class PdfNum extends PdfDataType {
 class PdfNumList extends PdfDataType {
   PdfNumList(this.values);
 
-  final List<num?> values;
+  final List<num> values;
 
   @override
   void output(PdfStream s) {
@@ -123,7 +123,7 @@ class PdfNumList extends PdfDataType {
       if (n > 0) {
         s.putByte(0x20);
       }
-      PdfNum(values[n]!).output(s);
+      PdfNum(values[n]).output(s);
     }
   }
 
@@ -448,13 +448,13 @@ class PdfArray<T extends PdfDataType> extends PdfDataType {
     }
   }
 
-  static PdfArray<PdfIndirect> fromObjects(List<PdfObject?> objects) {
+  static PdfArray<PdfIndirect> fromObjects(List<PdfObject> objects) {
     return PdfArray(
-        objects.map<PdfIndirect>((PdfObject? e) => e!.ref()).toList());
+        objects.map<PdfIndirect>((PdfObject e) => e.ref()).toList());
   }
 
-  static PdfArray<PdfNum> fromNum(List<num?> list) {
-    return PdfArray(list.map<PdfNum>((num? e) => PdfNum(e!)).toList());
+  static PdfArray<PdfNum> fromNum(List<num> list) {
+    return PdfArray(list.map<PdfNum>((num e) => PdfNum(e)).toList());
   }
 
   final List<T> values = <T>[];

@@ -111,13 +111,13 @@ class PdfGraphics {
   late _PdfGraphicsContext _context;
   final Queue<_PdfGraphicsContext> _contextQueue = Queue<_PdfGraphicsContext>();
 
-  final PdfGraphicStream? _page;
+  final PdfGraphicStream _page;
 
   /// Buffer where to write the graphic operations
   final PdfStream buf;
 
   /// Default font if none selected
-  PdfFont? get defaultFont => _page!.getDefaultFont();
+  PdfFont? get defaultFont => _page.getDefaultFont();
 
   /// Draw a surface on the previously defined shape
   /// set evenOdd to false to use the nonzero winding number rule to determine the region to fill and to true to use the even-odd rule to determine the region to fill
@@ -150,7 +150,7 @@ class PdfGraphics {
   /// Apply a shader
   void applyShader(PdfShading shader) {
     // The shader needs to be registered in the page resources
-    _page!.addShader(shader);
+    _page.addShader(shader);
     buf.putString('${shader.name} sh\n');
   }
 
@@ -179,7 +179,7 @@ class PdfGraphics {
     h ??= img.height.toDouble() * w / img.width.toDouble();
 
     // The image needs to be registered in the page resources
-    _page!.addXObject(img);
+    _page.addXObject(img);
 
     // q w 0 0 h x y cm % the coordinate matrix
     buf.putString('q ');
@@ -214,7 +214,7 @@ class PdfGraphics {
   }
 
   /// Draws a line between two coordinates.
-  void drawLine(double? x1, double? y1, double? x2, double? y2) {
+  void drawLine(double x1, double y1, double x2, double y2) {
     moveTo(x1, y1);
     lineTo(x2, y2);
   }
@@ -230,12 +230,12 @@ class PdfGraphics {
 
   /// Draws a Rectangle
   void drawRect(
-    double? x,
-    double? y,
-    double? w,
-    double? h,
+    double x,
+    double y,
+    double w,
+    double h,
   ) {
-    PdfNumList(<double?>[x, y, w, h]).output(buf);
+    PdfNumList([x, y, w, h]).output(buf);
     buf.putString(' re\n');
   }
 
@@ -297,18 +297,18 @@ class PdfGraphics {
     PdfFont font,
     double size,
     String s,
-    double? x,
+    double x,
     double y, {
-    double? charSpace = 0,
+    double charSpace = 0,
     double wordSpace = 0,
     double scale = 1,
-    PdfTextRenderingMode? mode = PdfTextRenderingMode.fill,
+    PdfTextRenderingMode mode = PdfTextRenderingMode.fill,
     double rise = 0,
   }) {
-    _page!.addFont(font);
+    _page.addFont(font);
 
     buf.putString('BT ');
-    PdfNumList(<double?>[x, y]).output(buf);
+    PdfNumList([x, y]).output(buf);
     buf.putString(' Td ');
     setFont(font, size,
         charSpace: charSpace,
@@ -358,20 +358,20 @@ class PdfGraphics {
   /// Sets the fill pattern for drawing
   void setFillPattern(PdfPattern pattern) {
     // The shader needs to be registered in the page resources
-    _page!.addPattern(pattern);
+    _page.addPattern(pattern);
     buf.putString('/Pattern cs${pattern.name} scn\n');
   }
 
   /// Sets the stroke pattern for drawing
   void setStrokePattern(PdfPattern pattern) {
     // The shader needs to be registered in the page resources
-    _page!.addPattern(pattern);
+    _page.addPattern(pattern);
     buf.putString('/Pattern CS${pattern.name} SCN\n');
   }
 
   /// Set the graphic state for drawing
   void setGraphicState(PdfGraphicState state) {
-    final name = _page!.stateName(state);
+    final name = _page.stateName(state);
     buf.putString('$name gs\n');
   }
 
@@ -389,14 +389,14 @@ class PdfGraphics {
   }
 
   /// This adds a line segment to the current path
-  void lineTo(double? x, double? y) {
-    PdfNumList(<double?>[x, y]).output(buf);
+  void lineTo(double x, double y) {
+    PdfNumList([x, y]).output(buf);
     buf.putString(' l\n');
   }
 
   /// This moves the current drawing point.
-  void moveTo(double? x, double? y) {
-    PdfNumList(<double?>[x, y]).output(buf);
+  void moveTo(double x, double y) {
+    PdfNumList([x, y]).output(buf);
     buf.putString(' m\n');
   }
 
@@ -404,8 +404,8 @@ class PdfGraphics {
   /// using (x1,y1) as the control point at the beginning of the curve
   /// and (x2,y2) as the control point at the end of the curve.
   void curveTo(
-      double? x1, double? y1, double? x2, double? y2, double? x3, double? y3) {
-    PdfNumList(<double?>[x1, y1, x2, y2, x3, y3]).output(buf);
+      double x1, double y1, double x2, double y2, double x3, double y3) {
+    PdfNumList([x1, y1, x2, y2, x3, y3]).output(buf);
     buf.putString(' c\n');
   }
 
@@ -524,7 +524,7 @@ class PdfGraphics {
   /// the constraints imposed by the other parameters. large and sweep flags
   /// contribute to the automatic calculations and help determine how the arc is drawn.
   void bezierArc(
-      double? x1, double? y1, double rx, double ry, double? x2, double? y2,
+      double x1, double y1, double rx, double ry, double x2, double y2,
       {bool large = false, bool sweep = false, double phi = 0.0}) {
     if (x1 == x2 && y1 == y2) {
       // From https://www.w3.org/TR/SVG/implnote.html#ArcImplementationNotes:
@@ -542,12 +542,12 @@ class PdfGraphics {
       // Our box bézier arcs can't handle rotations directly
       // move to a well known point, eliminate phi and transform the other point
       final mat = Matrix4.identity();
-      mat.translate(-x1!, -y1!);
+      mat.translate(-x1, -y1);
       mat.rotateZ(-phi);
-      final tr = mat.transform3(Vector3(x2!, y2!, 0));
+      final tr = mat.transform3(Vector3(x2, y2, 0));
       _endToCenterParameters(0, 0, tr[0], tr[1], large, sweep, rx, ry);
     } else {
-      _endToCenterParameters(x1!, y1!, x2!, y2!, large, sweep, rx, ry);
+      _endToCenterParameters(x1, y1, x2, y2, large, sweep, rx, ry);
     }
   }
 

@@ -64,7 +64,7 @@ class PdfShading extends PdfObject {
 
     params['/ShadingType'] = PdfNum(shadingType.index + 2);
     if (boundingBox != null) {
-      params['/BBox'] = PdfArray.fromNum(<double?>[
+      params['/BBox'] = PdfArray.fromNum([
         boundingBox!.left,
         boundingBox!.bottom,
         boundingBox!.right,
@@ -75,13 +75,12 @@ class PdfShading extends PdfObject {
     params['/ColorSpace'] = const PdfName('/DeviceRGB');
 
     if (shadingType == PdfShadingType.axial) {
-      params['/Coords'] =
-          PdfArray.fromNum(<double?>[start.x, start.y, end.x, end.y]);
+      params['/Coords'] = PdfArray.fromNum([start.x, start.y, end.x, end.y]);
     } else if (shadingType == PdfShadingType.radial) {
       assert(radius0 != null);
       assert(radius1 != null);
       params['/Coords'] = PdfArray.fromNum(
-          <double?>[start.x, start.y, radius0, end.x, end.y, radius1]);
+          [start.x, start.y, radius0!, end.x, end.y, radius1!]);
     }
     // params['/Domain'] = PdfArray.fromNum(<num>[0, 1]);
     if (extendStart || extendEnd) {

@@ -30,19 +30,19 @@ class PdfSoftMask {
       bool knockout = false,
       bool invert = false}) {
     _mask = PdfGraphicXObject(document);
-    _mask!.params['/BBox'] = PdfArray.fromNum([
+    _mask.params['/BBox'] = PdfArray.fromNum([
       boundingBox.x,
       boundingBox.y,
       boundingBox.width,
       boundingBox.height,
     ]);
     if (isolated) {
-      _mask!.params['/I'] = const PdfBool(true);
+      _mask.params['/I'] = const PdfBool(true);
     }
     if (knockout) {
-      _mask!.params['/K'] = const PdfBool(true);
+      _mask.params['/K'] = const PdfBool(true);
     }
-    _graphics = PdfGraphics(_mask, _mask!.buf);
+    _graphics = PdfGraphics(_mask, _mask.buf);
 
     if (invert) {
       _tr = PdfFunction(
@@ -54,7 +54,7 @@ class PdfSoftMask {
 
   final PdfDocument document;
 
-  PdfGraphicXObject? _mask;
+  late PdfGraphicXObject _mask;
 
   PdfGraphics? _graphics;
 
@@ -65,7 +65,7 @@ class PdfSoftMask {
   PdfDict output() {
     final params = PdfDict({
       '/S': const PdfName('/Luminosity'),
-      '/G': _mask!.ref(),
+      '/G': _mask.ref(),
     });
 
     if (_tr != null) {

@@ -55,7 +55,7 @@ abstract class _Span {
 
   void paint(
     Context context,
-    TextStyle? style,
+    TextStyle style,
     double textScaleFactor,
     PdfPoint point,
   );
@@ -261,18 +261,18 @@ class _Word extends _Span {
   @override
   void paint(
     Context context,
-    TextStyle? style,
+    TextStyle style,
     double textScaleFactor,
     PdfPoint point,
   ) {
     context.canvas.drawString(
-      style!.font!.getFont(context)!,
+      style.font!.getFont(context)!,
       style.fontSize! * textScaleFactor,
       text,
       point.x + offset.x,
       point.y + offset.y,
-      mode: style.renderingMode,
-      charSpace: style.letterSpacing,
+      mode: style.renderingMode ?? PdfTextRenderingMode.fill,
+      charSpace: style.letterSpacing ?? 0,
     );
   }
 
@@ -312,10 +312,10 @@ class _WidgetSpan extends _Span {
   double get top => 0;
 
   @override
-  double? get width => widget.box!.width;
+  double get width => widget.box!.width;
 
   @override
-  double? get height => widget.box!.height;
+  double get height => widget.box!.height;
 
   @override
   PdfPoint get offset => widget.box!.offset;
@@ -755,7 +755,7 @@ class RichText extends Widget {
           style,
         );
 
-        if (offsetX + ws.width! > constraintWidth && spanCount > 0) {
+        if (offsetX + ws.width > constraintWidth && spanCount > 0) {
           overflow = true;
           lines.add(_Line(
             this,
@@ -786,8 +786,8 @@ class RichText extends Widget {
         final baseline = span.baseline! * textScaleFactor;
         top = math.min(top ?? baseline, baseline);
         bottom = math.max(
-          bottom ?? ws.height! + baseline,
-          ws.height! + baseline,
+          bottom ?? ws.height + baseline,
+          ws.height + baseline,
         );
 
         ws.offset = PdfPoint(offsetX, -offsetY + baseline);
@@ -804,7 +804,7 @@ class RichText extends Widget {
           ),
         );
 
-        offsetX += ws.left + ws.width!;
+        offsetX += ws.left + ws.width;
       }
 
       return true;
@@ -897,7 +897,7 @@ class RichText extends Widget {
 
       span.paint(
         context,
-        currentStyle,
+        currentStyle!,
         textScaleFactor,
         PdfPoint(box!.left, box!.top),
       );