chemtext: Add escaping of characters with special treatment

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@5963 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/chemtext/demo/chemdemo/testchem.lfm

@@ -83,17 +83,17 @@ object Form1: TForm1
       Width = 17
       Shape = bsSpacer
     end
-    object Label1: TLabel
+    object Label3: TChemLabel
       AnchorSideRight.Control = Spacer
-      Left = 103
+      Left = 16
       Height = 18
-      Top = 40
+      Top = 96
-      Width = 67
+      Width = 154
       Anchors = [akTop, akRight]
-      Caption = 'Propanol:'
+      Caption = 'Ion\-molecule reaction:'
       ParentColor = False
     end
-    object Label2: TLabel
+    object Label2: TChemLabel
       AnchorSideRight.Control = Spacer
       Left = 40
       Height = 18
@@ -103,14 +103,14 @@ object Form1: TForm1
       Caption = 'Chemical reaction:'
       ParentColor = False
     end
-    object Label3: TLabel
+    object Label1: TChemLabel
       AnchorSideRight.Control = Spacer
-      Left = 19
+      Left = 103
       Height = 18
-      Top = 96
+      Top = 40
-      Width = 151
+      Width = 67
       Anchors = [akTop, akRight]
-      Caption = 'Ion-molecule reaction:'
+      Caption = 'Propanol:'
       ParentColor = False
     end
   end

components/chemtext/demo/chemdemo/testchem.pas

@@ -11,17 +11,17 @@ type
   { TForm1 }
 
   TForm1 = class(TForm)
+    Label1: TChemLabel;
+    Label2: TChemLabel;
+    Label3: TChemLabel;
     Label4: TLabel;
     Spacer: TBevel;
     ChemLabel1: TChemLabel;
     ChemLabel2: TChemLabel;
     ChemLabel3: TChemLabel;
+    ChemLabel4: TChemLabel;
     ChemLabel5: TChemLabel;
     Edit1: TEdit;
-    ChemLabel4: TChemLabel;
-    Label1: TLabel;
-    Label2: TLabel;
-    Label3: TLabel;
     Panel1: TPanel;
     procedure Edit1Change(Sender: TObject);
   private

components/chemtext/source/chemtext.pas

@@ -133,6 +133,7 @@ const
   SUBFONT_OFFSET_MULTIPLIER = 50;
   SUBFONT_DIVISOR = 100;
   ARROW_LINE: array[boolean] of char = ('-', '=');
+  ESCAPE_CHAR = '\';
 
 function ChemTextHeight(ACanvas: TCanvas; const AText: String;
   Arrow: TChemArrow = caAsciiSingle): Integer;
@@ -236,6 +237,7 @@ var
   i, j: integer;
   s: string;
   subNos: boolean;        // "subscript numbers"
+  escaping: Boolean;
 begin
   Result := Size(0, 0);
   if AText = '' then
@@ -249,73 +251,86 @@ begin
 
     x0 := X;
     subNos := false;
+    escaping := false;
     i := 1;
     while i <= Length(AText) do begin
-      case AText[i] of
+      if escaping then
-        '0'..'9':
+      begin
-          begin
+        DrawNormal(X, Y, AText[i]);
-            s := AText[i];
+        escaping := false;
-            j := i+1;
+      end else
-            while (j <= Length(AText)) and (AText[j] in ['0'..'9']) do
+        case AText[i] of
-              inc(j);
+          '0'..'9':
-            s := Copy(AText, i, j-i);
-            if subNos then
-              DrawSub(X, Y, s)
-            else
-              DrawNormal(X, Y, s);
-            i := j-1;
-            subNos := false;
-          end;
-
-        '<':
-          begin
-            j := i+1;
-            while (j <= Length(AText)) and (AText[j] in ['-', '=']) do
-              inc(j);
-            if (AText[j] = '>') then
-              DrawArrow(X, Y, adBoth, j-i-1)
-            else begin
-              DrawArrow(X, Y, adLeft, j-i-1);
-              dec(j);
-            end;
-            i := j;
-            subNos := false;
-          end;
-
-        '+':
-          begin
-            if (i > 1) and (AText[i-1] in ['A'..'Z','a'..'z','0'..'9','+',')']) then
-              DrawSup(X, Y, '+')
-            else
-              DrawNormal(X, Y, '+');
-            subNos := false;
-          end;
-
-        '-':
-          begin
-            j := i+1;
-            while (j <= Length(AText)) and (AText[j] = '-') do inc(j);
-            if (j <= Length(AText)) and (AText[j] = '>') then  // Arrow
             begin
-              DrawArrow(X, y, adRight, j-i);
+              s := AText[i];
-              i := j;
+              j := i+1;
-            end else                  // superscript -
+              while (j <= Length(AText)) and (AText[j] in ['0'..'9']) do
-              DrawSup(X, Y, '-');
+                inc(j);
-            subNos := false;
+              s := Copy(AText, i, j-i);
-          end;
+              if subNos then
+                DrawSub(X, Y, s)
+              else
+                DrawNormal(X, Y, s);
+              i := j-1;
+              subNos := false;
+            end;
 
-        else
+          '<':
-          begin
+            begin
-            j := i+1;
+              j := i+1;
-            while (j <= Length(AText)) and not (AText[j] in ['0'..'9', '+', '-', '<']) do
+              while (j <= Length(AText)) and (AText[j] in ['-', '=']) do
-              inc(j);
+                inc(j);
-            s := Copy(AText, i, j-i);
+              if (AText[j] = '>') then
-            DrawNormal(X, Y, s);
+                DrawArrow(X, Y, adBoth, j-i-1)
-            i := j-1;
+              else begin
-            subNos := AText[i] in ['A'..'Z', 'a'..'z', ')'];
+                DrawArrow(X, Y, adLeft, j-i-1);
-              // In these cases a subsequent number will be subscripted.
+                dec(j);
-          end;
+              end;
-      end;
+              i := j;
+              subNos := false;
+            end;
+
+          '+':
+            begin
+              if (i > 1) and (AText[i-1] in ['A'..'Z','a'..'z','0'..'9','+',')']) then
+                DrawSup(X, Y, '+')
+              else
+                DrawNormal(X, Y, '+');
+              subNos := false;
+            end;
+
+          '-':
+            begin
+              begin
+                j := i+1;
+                while (j <= Length(AText)) and (AText[j] = '-') do inc(j);
+                if (j <= Length(AText)) and (AText[j] = '>') then  // Arrow
+                begin
+                  DrawArrow(X, y, adRight, j-i);
+                  i := j;
+                end else                  // superscript -
+                  DrawSup(X, Y, '-');
+              end;
+              subNos := false;
+            end;
+
+          ESCAPE_CHAR:
+            escaping := true;
+
+          else
+            begin
+              j := i+1;
+              while (j <= Length(AText)) and
+                    not (AText[j] in ['0'..'9', '+', '-', '<', ESCAPE_CHAR])
+              do
+                inc(j);
+              s := Copy(AText, i, j-i);
+              DrawNormal(X, Y, s);
+              i := j-1;
+              subNos := AText[i] in ['A'..'Z', 'a'..'z', ')'];
+                // In these cases a subsequent number will be subscripted.
+            end;
+        end;
       inc(i);
     end;
   end;