Author: AlbrechtS
Date: 2009-04-07 10:33:22 -0700 (Tue, 07 Apr 2009)
New Revision: 6743
Log:
Fix image handling in Fl_Help_View (STR #2163 and STR #2004).

src/Fl_Help_View.cxx:

This fix is the first step and compatible with FLTK 1.1 (keeping the ABI).
The next step should be to manage the loaded images in an own structure,
because we must know exactly, when to release() the images. The previous
version would release images too many times and could release shared
images that had been loaded by another part of the program (maybe even
another Fl_Help_View widget).

FL/Fl_Help_View.H:

Doxygen comments improved.


Modified:
   branches/branch-1.3/FL/Fl_Help_View.H
   branches/branch-1.3/src/Fl_Help_View.cxx

Modified: branches/branch-1.3/FL/Fl_Help_View.H
===================================================================
--- branches/branch-1.3/FL/Fl_Help_View.H       2009-04-07 17:25:24 UTC (rev 
6742)
+++ branches/branch-1.3/FL/Fl_Help_View.H       2009-04-07 17:33:22 UTC (rev 
6743)
@@ -87,7 +87,7 @@
  * Fl_Help_View font stack opaque implementation
  */
 
-/** Fl_Help_View font stack element definition */
+/** Fl_Help_View font stack element definition. */
 struct Fl_Help_Font_Style {
   Fl_Font      f;  ///< Font
   Fl_Fontsize  s;  ///< Font Size
@@ -98,11 +98,11 @@
   Fl_Help_Font_Style(){} // For in table use
 };
 
-/** Fl_Help_View font stack definition */
+/** Fl_Help_View font stack definition. */
 const size_t MAX_FL_HELP_FS_ELTS = 100;
 
 struct Fl_Help_Font_Stack {
-  /** font stack construction, initialize attributes.*/
+  /** font stack construction, initialize attributes. */
   Fl_Help_Font_Stack() {
     nfonts_ = 0;
   }
@@ -113,7 +113,7 @@
     fl_font(f, s); 
     fl_color(c);
   }
-  /** Gets the top (current) elt on the stack */
+  /** Gets the top (current) element on the stack. */
   void top(Fl_Font &f, Fl_Fontsize &s, Fl_Color &c) { elts_[nfonts_].get(f, s, 
c); }
   /** Pushes the font style triplet on the stack, also calls fl_font() & 
fl_color() adequately */
   void push(Fl_Font f, Fl_Fontsize s, Fl_Color c) { 
@@ -127,8 +127,8 @@
     top(f, s, c);
     fl_font(f, s); fl_color(c);
   }
-  /** Gets the current count of font style elts in the stack */
-  size_t count() const {return nfonts_;} /// Gets the current number of fonts 
in the stack
+  /** Gets the current count of font style elements in the stack. */
+  size_t count() const {return nfonts_;} // Gets the current number of fonts 
in the stack
 
 protected:
   size_t nfonts_;              ///< current number of fonts in stack
@@ -148,7 +148,7 @@
   elements are supported, as well as a primitive implementation of tables.
   GIF, JPEG, and PNG images are displayed inline.
 */
-class FL_EXPORT Fl_Help_View : public Fl_Group //// Help viewer widget
+class FL_EXPORT Fl_Help_View : public Fl_Group // Help viewer widget
 {
   enum { RIGHT = -1, CENTER, LEFT };   ///< Alignments
 
@@ -234,10 +234,10 @@
 
   Fl_Help_View(int xx, int yy, int ww, int hh, const char *l = 0);
   ~Fl_Help_View();
-  /**    This method returns the current directory for the text in the buffer. 
 */
+  /** Returns the current directory for the text in the buffer. */
   const char   *directory() const { if (directory_[0]) return (directory_);
                                        else return ((const char *)0); }
-  /**    This method returns the current filename for the text in the buffer.  
*/
+  /** Returns the current filename for the text in the buffer. */
   const char   *filename() const { if (filename_[0]) return (filename_);
                                        else return ((const char *)0); }
   int          find(const char *s, int p = 0);
@@ -266,7 +266,7 @@
   void         link(Fl_Help_Func *fn) { link_ = fn; }
   int          load(const char *f);
   void         resize(int,int,int,int);
-  /** Gets the size of the Help view */
+  /** Gets the size of the help view. */
   int          size() const { return (size_); }
   void         size(int W, int H) { Fl_Widget::size(W, H); }
   /** Sets the default text color. */
@@ -285,12 +285,12 @@
   const char   *title() { return (title_); }
   void         topline(const char *n);
   void         topline(int);
-  /** Returns the current top line in pixels.  */
+  /** Returns the current top line in pixels. */
   int          topline() const { return (topline_); }
   void         leftline(int);
-  /** Gets the left position. */
+  /** Gets the left position in pixels. */
   int          leftline() const { return (leftline_); }
-  void         value(const char *v);
+  void         value(const char *val);
   /** Returns the current buffer contents. */
   const char   *value() const { return (value_); }
   void          clear_selection();
@@ -301,7 +301,7 @@
     If this value is zero (default), this widget will use the 
     Fl::scrollbar_size() value as the scrollbar's width.
   
-    \returns Scrollbar size in pixels, or 0 if the global Fl::scrollsize() is 
being used.
+    \returns Scrollbar size in pixels, or 0 if the global Fl::scrollbar_size() 
is being used.
     \see Fl::scrollbar_size(int)
   */
   int scrollbar_size() const {

Modified: branches/branch-1.3/src/Fl_Help_View.cxx
===================================================================
--- branches/branch-1.3/src/Fl_Help_View.cxx    2009-04-07 17:25:24 UTC (rev 
6742)
+++ branches/branch-1.3/src/Fl_Help_View.cxx    2009-04-07 17:33:22 UTC (rev 
6743)
@@ -96,7 +96,12 @@
 static void    scrollbar_callback(Fl_Widget *s, void *);
 static void    hscrollbar_callback(Fl_Widget *s, void *);
 
+//
+// global flag for image loading (see get_image).
+//
 
+static char initial_load = 0;
+
 //
 // Broken image...
 //
@@ -273,7 +278,7 @@
 }
 
 
-/** Add a text block to the list. */
+/** Adds a text block to the list. */
 Fl_Help_Block *                                        // O - Pointer to new 
block
 Fl_Help_View::add_block(const char   *s,       // I - Pointer to start of 
block text
                        int           xx,       // I - X position of block
@@ -314,7 +319,7 @@
 }
 
 
-/** Add a new link to the list. */
+/** Adds a new link to the list. */
 void Fl_Help_View::add_link(const char *n,     // I - Name of link
                       int        xx,   // I - X position of link
                      int        yy,    // I - Y position of link
@@ -381,7 +386,7 @@
   ntargets_ ++;
 }
 
-/** Compare two targets.*/
+/** Compares two targets.*/
 int                                                    // O - Result of 
comparison
 Fl_Help_View::compare_targets(const Fl_Help_Target *t0,        // I - First 
target
                              const Fl_Help_Target *t1) // I - Second target
@@ -389,7 +394,7 @@
   return (strcasecmp(t0->name, t1->name));
 }
 
-/** Compute the alignment for a line in a block.*/
+/** Computes the alignment for a line in a block.*/
 int                                            // O - New line
 Fl_Help_View::do_align(Fl_Help_Block *block,   // I - Block to add to
                       int          line,       // I - Current line
@@ -428,7 +433,7 @@
   return (line);
 }
 
-/** Draw the Fl_Help_View widget.*/
+/** Draws the Fl_Help_View widget. */
 void
 Fl_Help_View::draw()
 {
@@ -881,10 +886,6 @@
            if (img) {
              img->draw(xx + x() - leftline_,
                        yy + y() - fl_height() + fl_descent() + 2);
-#if !defined(WIN32) && !defined(__APPLE__)
-             if ((void*)img != &broken_image)
-#endif 
-               if(img->refcount()>0) img->release();
            }
 
            xx += ww;
@@ -990,8 +991,10 @@
 
 
 
-/** Find the specified string s at starting position p, return the matching 
pos 
-    or -1 if not found */
+/** Finds the specified string \p s at starting position \p p.
+
+    \return the matching position or -1 if not found
+*/
 int                                            // O - Matching position or -1 
if not found
 Fl_Help_View::find(const char *s,              // I - String to find
                    int        p)               // I - Starting position
@@ -1049,7 +1052,7 @@
   return (-1);
 }
 
-/** Format the help text.*/
+/** Formats the help text. */
 void Fl_Help_View::format() {
   int          i;              // Looping var
   int          done;           // Are we done yet?
@@ -1864,7 +1867,7 @@
 }
 
 
-/** Format a table */
+/** Formats a table */
 void
 Fl_Help_View::format_table(int        *table_width,    // O - Total table width
                            int        *columns,                // O - Column 
widths
@@ -2298,7 +2301,7 @@
 }
 
 
-/** Free memory used for the document. */
+/** Frees memory used for the document. */
 void
 Fl_Help_View::free_data() {
   // Release all images...
@@ -2311,7 +2314,6 @@
                wattr[1024],    // Width attribute buffer
                hattr[1024];    // Height attribute buffer
 
-
     for (ptr = value_; *ptr;)
     {
       if (*ptr == '<')
@@ -2354,19 +2356,17 @@
          int           width;
          int           height;
 
-
           get_attr(attrs, "WIDTH", wattr, sizeof(wattr));
           get_attr(attrs, "HEIGHT", hattr, sizeof(hattr));
          width  = get_length(wattr);
          height = get_length(hattr);
 
          if (get_attr(attrs, "SRC", attr, sizeof(attr))) {
-           // Release the image twice to free it from memory...
+           // Get and release the image to free it from memory...
            img = get_image(attr, width, height);
-#if !defined(__APPLE__)
-           if ((void*)img!=&broken_image)
-#endif 
-             while (img->refcount()>0) img->release();
+           if ((void*)img != &broken_image) {
+             img->release();
+           }
          }
        }
       }
@@ -2404,7 +2404,7 @@
   }
 }
 
-/** Get an alignment attribute. */
+/** Gets an alignment attribute. */
 int                                    // O - Alignment
 Fl_Help_View::get_align(const char *p, // I - Pointer to start of attrs
                         int        a)  // I - Default alignment
@@ -2424,7 +2424,7 @@
 }
 
 
-/** Get an attribute value from the string. */
+/** Gets an attribute value from the string. */
 const char *                                   // O - Pointer to buf or NULL
 Fl_Help_View::get_attr(const char *p,          // I - Pointer to start of 
attributes
                       const char *n,           // I - Name of attribute
@@ -2496,7 +2496,7 @@
 }
 
 
-/** Get an alignment attribute. */
+/** Gets a color attribute. */
 Fl_Color                               // O - Color value
 Fl_Help_View::get_color(const char *n, // I - Color name
                         Fl_Color   c)  // I - Default color value
@@ -2555,7 +2555,48 @@
 }
 
 
-/** Gets an inline image. */
+/** Gets an inline image.
+
+  The image reference count is maintained accordingly, such that
+  the image can be released exactly once when the document is closed.
+
+  \return a pointer to a cached Fl_Shared_Image, if the image can be loaded,
+         otherwise a pointer to an internal Fl_Pixmap (broken_image).
+
+  \todo Fl_Help_View::get_image() returns a pointer to the internal
+  Fl_Pixmap broken_image, but this is _not_ compatible with the
+  return type Fl_Shared_Image (release() must not be called).
+*/
+
+/* Implementation note: (A.S. Apr 05, 2009)
+
+  Fl_Help_View::get_image() uses a static global flag (initial_load)
+  to determine, if it is called from the initial loading of a document
+  (load() or value()), or from resize() or draw().
+
+  A better solution would be to manage all loaded images in an own
+  structure like Fl_Help_Target (Fl_Help_Image ?) to avoid using this
+  global flag, but this would break the ABI !
+
+  This should be fixed in FLTK 1.3 !
+
+
+  If initial_load is true, then Fl_Shared_Image::get() is called to
+  load the image, and the reference count of the shared image is
+  increased by one.
+
+  If initial_load is false, then Fl_Shared_Image::find() is called to
+  load the image, and the image is released immediately. This avoids
+  increasing the reference count when calling get_image() from draw()
+  or resize().
+
+  Calling Fl_Shared_Image::find() instead of Fl_Shared_Image::get() avoids
+  doing unnecessary i/o for "broken images" within each resize/redraw.
+
+  Each image must be released exactly once in the destructor or before
+  a new document is loaded: see free_data().
+*/
+
 Fl_Shared_Image *
 Fl_Help_View::get_image(const char *name, int W, int H) {
   const char   *localname;             // Local filename
@@ -2596,8 +2637,17 @@
 
   if (strncmp(localname, "file:", 5) == 0) localname += 5;
 
-  if ((ip = Fl_Shared_Image::get(localname, W, H)) == NULL)
-    ip = (Fl_Shared_Image *)&broken_image;
+  if (initial_load) {
+    if ((ip = Fl_Shared_Image::get(localname, W, H)) == NULL) {
+      ip = (Fl_Shared_Image *)&broken_image;
+    }
+  } else { // draw or resize
+    if ((ip = Fl_Shared_Image::find(localname, W, H)) == NULL) {
+      ip = (Fl_Shared_Image *)&broken_image;
+    } else {
+      ip->release();
+    }
+  }
 
   return ip;
 }
@@ -2640,6 +2690,7 @@
   char         target[32];     // Current target
 
   clear_selection();
+  free_data();
 
   strlcpy(target, linkp->name, sizeof(target));
 
@@ -2699,7 +2750,7 @@
   if (current_view==this)
     clear_global_selection();
 }
-/** Selects All the text in the view. */
+/** Selects all the text in the view. */
 void Fl_Help_View::select_all()
 {
   clear_global_selection();
@@ -2886,7 +2937,7 @@
 
 #define ctrl(x) ((x)&0x1f)
 
-/** Handle events in the widget. */
+/** Handles events in the widget. */
 int                            // O - 1 if we handled it, 0 otherwise
 Fl_Help_View::handle(int event)        // I - Event to handle
 {
@@ -3034,23 +3085,24 @@
 }
 
 
-/** Destroy a Fl_Help_View widget. */
-Fl_Help_View::~Fl_Help_View()
-/**
+/** Destroys the Fl_Help_View widget.
+
   The destructor destroys the widget and frees all memory that has been
-  allocated for the current file.
+  allocated for the current document.
 */
+Fl_Help_View::~Fl_Help_View()
 {
   clear_selection();
   free_data();
 }
 
 
-/** Load the specified file. */
+/** Loads the specified file.
 
+  This method loads the specified file or URL.
+*/
 int                            // O - 0 on success, -1 on error
 Fl_Help_View::load(const char *f)// I - Filename to load (may also have target)
-/**  This method loads the specified file or URL.*/
 {
   FILE         *fp;            // File to read from
   long         len;            // Length of file
@@ -3060,6 +3112,7 @@
   char         error[1024];    // Error buffer
   char         newname[1024];  // New filename buffer
 
+  // printf("load(%s)\n",f); fflush(stdout);
 
   if (strncmp(f, "ftp:", 4) == 0 ||
       strncmp(f, "http:", 5) == 0 ||
@@ -3083,6 +3136,8 @@
       if (!localname)
        return (0);
 
+      free_data();
+
       strlcpy(filename_, newname, sizeof(filename_));
       strlcpy(directory_, newname, sizeof(directory_));
 
@@ -3106,6 +3161,7 @@
   }
 
   clear_selection();
+  free_data();
 
   strlcpy(newname, f, sizeof(newname));
   if ((target = strrchr(newname, '#')) != NULL)
@@ -3129,12 +3185,6 @@
   else if (slash > directory_ && slash[-1] != '/')
     *slash = '\0';
 
-  if (value_ != NULL)
-  {
-    free((void *)value_);
-    value_ = NULL;
-  }
-
   if (strncmp(localname, "file:", 5) == 0)
     localname += 5;    // Adjust for local filename...
 
@@ -3159,7 +3209,9 @@
     value_ = strdup(error);
   }
 
+  initial_load = 1;
   format();
+  initial_load = 0;
 
   if (target)
     topline(target);
@@ -3170,7 +3222,7 @@
 }
 
 
-/** Resize the help widget. */
+/** Resizes the help widget. */
 
 void
 Fl_Help_View::resize(int xx,   // I - New left position
@@ -3195,7 +3247,10 @@
 }
 
 
-/** Scroll the text to the indicated position,  given a named destination */
+/** Scrolls the text to the indicated position, given a named destination.
+
+  \param[in] n target name
+*/
 void
 Fl_Help_View::topline(const char *n)   // I - Target name
 {
@@ -3216,21 +3271,26 @@
 }
 
 
+/** Scrolls the text to the indicated position, given a pixel line.
 
-/** Scroll the text to the indicated position,  given a pixel line. */
+  If the given pixel value \p top is out of range, then the text is
+  scrolled to the top or bottom of the document, resp.
+
+  \param[in] top top line number in pixels (0 = start of document)
+*/
 void
-Fl_Help_View::topline(int t)   // I - Top line number
+Fl_Help_View::topline(int top) // I - Top line number
 {
   if (!value_)
     return;
 
   int scrollsize = scrollbar_size_ ? scrollbar_size_ : Fl::scrollbar_size();
-  if (size_ < (h() - scrollsize) || t < 0)
-    t = 0;
-  else if (t > size_)
-    t = size_;
+  if (size_ < (h() - scrollsize) || top < 0)
+    top = 0;
+  else if (top > size_)
+    top = size_;
 
-  topline_ = t;
+  topline_ = top;
 
   scrollbar_.value(topline_, h() - scrollsize, 0, size_);
 
@@ -3240,22 +3300,26 @@
 }
 
 
+/** Scrolls the text to the indicated position, given a pixel column.
 
+  If the given pixel value \p left is out of range, then the text is
+  scrolled to the left or right side of the document, resp.
 
-/** Sets the left position. */
+  \param[in] left left column number in pixels (0 = left side)
+*/
 void
-Fl_Help_View::leftline(int l)  // I - Left position
+Fl_Help_View::leftline(int left)       // I - Left position
 {
   if (!value_)
     return;
 
   int scrollsize = scrollbar_size_ ? scrollbar_size_ : Fl::scrollbar_size();
-  if (hsize_ < (w() - scrollsize) || l < 0)
-    l = 0;
-  else if (l > hsize_)
-    l = hsize_;
+  if (hsize_ < (w() - scrollsize) || left < 0)
+    left = 0;
+  else if (left > hsize_)
+    left = hsize_;
 
-  leftline_ = l;
+  leftline_ = left;
 
   hscrollbar_.value(leftline_, w() - scrollsize, 0, hsize_);
 
@@ -3263,32 +3327,42 @@
 }
 
 
-/** Sets the current help text buffer to the string provided and reformats the 
text. */
+/** Sets the current help text buffer to the string provided and reformats the 
text.
+
+  The provided character string \p val is copied internally and will be
+  freed when value() is called again, or when the widget is destroyed.
+
+  If \p val is NULL, then the widget is cleared.
+*/
 void
-Fl_Help_View::value(const char *v)     // I - Text to view
+Fl_Help_View::value(const char *val)   // I - Text to view
 {
   clear_selection();
   free_data();
   set_changed();
 
-  if (!v)
+  if (!val)
     return;
 
-  value_ = strdup(v);
+  value_ = strdup(val);
 
+  initial_load = 1;
   format();
+  initial_load = 0;
 
   topline(0);
   leftline(0);
 }
 
+
 #ifdef ENC
 # undef ENC
 #endif
 // part b in the table seems to be mac_roman - beku
 # define ENC(a, b) a
 
-/** Return the character code associated with a quoted char. */
+
+/** Returns the character code associated with a quoted char. */
 static int                     // O - Code or -1 on error
 quote_char(const char *p) {    // I - Quoted string
   int  i;                      // Looping var
@@ -3418,7 +3492,7 @@
 }
 
 
-/** The scrollbar callback. */
+/** The vertical scrollbar callback. */
 static void
 scrollbar_callback(Fl_Widget *s, void *)
 {
@@ -3426,7 +3500,7 @@
 }
 
 
-/** The horizontal scrollbar callback . */
+/** The horizontal scrollbar callback. */
 static void
 hscrollbar_callback(Fl_Widget *s, void *)
 {

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