whats new ¦  programming tips ¦  indy articles ¦  intraweb articles ¦  informations ¦  links ¦  interviews
 misc ¦  tutorials ¦  Add&Win Game

Tips (1548)

Database (90)
Files (137)
Forms (107)
Graphic (116)
IDE (21)
Indy (5)
Internet / LAN (131)
IntraWeb (0)
Math (76)
Misc (127)
Multimedia (45)
Objects/
ActiveX (51)

OpenTools API (3)
Printing (35)
Strings (83)
System (268)
VCL (243)

Top15

Tips sort by
component


Search Tip

Add new Tip

Add&Win Game

Advertising

24 Visitors Online


 
...perform a backwards search in string (RichEdit) ?
Autor: P. Below
[ Print tip ]  

Tip Rating (2):  
     


Question:
I am using TDBImage to show a jpeg file, however, the resulting picture is
cropped by the size of the TDBImage control. I would like to show the whole
jpeg picture to the user, what can I do? I have turned on the "stretch"
property to true but the picture loses it shape (eg. Circle becomes an oval,
square becomes a rectangle).

Answer:
Using a TDBImage serves no purpose if you deal with JPEGs.
Use a normal TImage and draw the TJpegImage on its canvas using this:

{+------------------------------------------------------------
 | Function FindTextBackwards
 |
 | Parameters :
 |   findWhat: text to find
 |   inString: string to find it in
 |   startAt : character index to start at (1-based)
 |   caseSensitive: determines whether search is case-sensitive
 |   words   : if true the characters immediately surrounding
 |             a found location must not be alphanumeric
 | Returns    :
 |   character index (1-based) of first character of a found
 |   location, or 0, if the text was not found.
 | Description:
 |   Performs a simple sequential search for a string in a larger
 |   string, starting at the specified position and working towards
 |   the start of the string.
 | Error Conditions: none
 | Created: 27.02.99 by P. Below
 +------------------------------------------------------------}

function FindTextBackwards(findWhat, inString : string;
  startAt : integer;
  caseSensitive, words : boolean): integer;
var
  
i, patternlen, findpos : integer;
  lastchar, firstchar : char;
begin
  
Result := 0;  { assume failure }
  
patternlen := Length(findWhat);

  { Do a few sanity checks on the parameters }
  
if (patternlen = 0) or
    
(startAt < patternlen) or
    
(Length(inString) < patternlen) then
    
Exit;

  if not caseSensitive then 
  begin
    
{ convert both strings to lower case }
    
findWhat := AnsiLowercase(findWhat);
    inString := AnsiLowercase(inString);
  end{ If }

  
i := startAt;
  lastchar := findWhat[patternlen];
  firstchar := findWhat[1];

  while (Result = 0) and (i >= patternlen) do 
  begin
    if 
inString[i] = lastchar then 
    begin
      
findPos := i - patternlen + 1;
      if inString[findPos] = firstchar then 
      begin
        
{ We have a candidate. Compare the substring of length
          patternlen starting at findPos with findWhat. With
          AnsiStrLComp we can do that without having to copy
          the substring to a temp string first. }
        
if AnsiStrLComp(@findWhat[1], @inString[findPos],
          patternlen) = 0 then 
        begin
          
{ We have a match! }
          
Result := findPos;

          if words then 
          begin
            
{ Check the characters surrounding the hit. For the hit
              to constitute a word they must not be alphanumeric. }
            
if (findPos > 1) and
              
IsCharAlphanumeric(inString[findPos - 1]) then 
            begin
              
{ Not a match after all, <sigh>. }
              
Result := 0;
            end { If }
            
else 
            begin
              if 
(i < Length(inString)) and
                
IsCharAlphanumeric(inString[i + 1]) then 
              begin
                
{ Not a match after all, <sigh>. }
                
Result := 0;
              end{ If }
            
end{ Else }
          
end{ If }
        
end{ If }
      
end{ If }
    
end{ If }
    
Dec(i);
  end{ While }
end{ FindTextBackwards }

procedure TForm1.Button1Click(Sender : TObject);
var
  
findPos : integer;
begin
  
findPos := FindTextBackwards(findEdit.Text,
    richedit1.Text,
    richedit1.selstart + 1,
    caseCheckbox.Checked,
    wordsCheckbox.Checked);
  if findPos > 0 then 
  begin
    with 
richedit1 do 
    begin
      
selstart := findPos - 1;
      sellength := findEdit.GetTextLen;
      Perform(em_scrollcaret, 0, 0);
      SetFocus;
    end;
  end
  else
    
ShowMessage('Text not found');
end;

 

Rate this tip:

poor
very good


Copyright © by SwissDelphiCenter.ch
All trademarks are the sole property of their respective owners