mirror of https://github.com/fltk/fltk
207 lines
7.0 KiB
C++
207 lines
7.0 KiB
C++
//
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// Shared image header file for the Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2024 by Bill Spitzak and others.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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// file is missing or damaged, see the license at:
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//
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// https://www.fltk.org/COPYING.php
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//
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// Please see the following page on how to report bugs and issues:
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//
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// https://www.fltk.org/bugs.php
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//
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/** \file
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Fl_Shared_Image class. */
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#ifndef Fl_Shared_Image_H
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# define Fl_Shared_Image_H
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# include "Fl_Image.H"
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#undef SHIM_DEBUG
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/** Test function (typedef) for adding new shared image formats.
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This defines the function type you can use to add a handler for unknown
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image formats that can be opened and loaded as an Fl_Shared_Image.
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fl_register_images() adds all image formats known to FLTK.
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Call Fl_Shared_Image::add_handler() to add your own check function to
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the list of known image formats.
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Your function will be passed the filename (\p name), some \p header
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bytes already read from the image file and the size \p headerlen of the
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data read. The max value of size is implementation dependent. If your
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handler function needs to check more bytes you must open the image file
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yourself.
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The provided buffer \p header must not be overwritten.
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If your handler function can identify the file type you must open the
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file and return a valid Fl_Image or derived type, otherwise you must
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return \c NULL.
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Example:
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\code
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static Fl_Image *check_my_image(const char *name,
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uchar *header,
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int headerlen) {
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// (test image type using header and headerlen)
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if (known) {
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// (load image data from file \p name)
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return new Fl_RGB_Image(data, ...);
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} else
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return 0;
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}
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// add your handler:
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Fl_Shared_Image::add_handler(check_my_image);
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\endcode
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\param[in] name filename to be checked and opened if applicable
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\param[in] header portion of the file that has already been read
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\param[in] headerlen length of provided \p header data
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\returns valid Fl_Image or \c NULL.
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\see Fl_Shared_Image::add_handler()
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*/
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typedef Fl_Image *(*Fl_Shared_Handler)(const char *name,
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uchar *header,
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int headerlen);
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/**
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This class supports caching, loading, and drawing of image files.
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Most applications will also want to link against the fltk_images library
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and call the fl_register_images() function to support standard image
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formats such as BMP, GIF, JPEG, PNG, and SVG (unless the library was built
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with the option removing SVG support).
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Images can be requested (loaded) with Fl_Shared_Image::get(), find(),
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and some other methods. All images are cached in an internal list of
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shared images and should be released when they are no longer needed.
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A refcount is used to determine if a released image is to be destroyed
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with delete.
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\see fl_register_image()
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\see Fl_Shared_Image::get()
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\see Fl_Shared_Image::find()
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\see Fl_Shared_Image::release()
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*/
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class FL_EXPORT Fl_Shared_Image : public Fl_Image {
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friend class Fl_JPEG_Image;
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friend class Fl_PNG_Image;
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friend class Fl_SVG_Image;
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friend class Fl_Graphics_Driver;
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protected:
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static Fl_Shared_Image **images_; // Shared images
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static int num_images_; // Number of shared images
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static int alloc_images_; // Allocated shared images
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static Fl_Shared_Handler *handlers_; // Additional format handlers
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static int num_handlers_; // Number of format handlers
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static int alloc_handlers_; // Allocated format handlers
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const char *name_; // Name of image file
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int original_; // Original image?
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int refcount_; // Number of times this image has been used
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Fl_Image *image_; // The image that is shared
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int alloc_image_; // Was the image allocated?
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static int compare(Fl_Shared_Image **i0, Fl_Shared_Image **i1);
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// Use get() and release() to load/delete images in memory...
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Fl_Shared_Image();
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Fl_Shared_Image(const char *n, Fl_Image *img = 0);
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virtual ~Fl_Shared_Image();
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void add();
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void update();
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Fl_Shared_Image *copy_(int W, int H) const;
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public:
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#ifdef SHIM_DEBUG
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static void print_pool();
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#endif
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/** Returns the filename of the shared image */
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const char *name() { return name_; }
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/** Returns the number of references of this shared image.
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When reference is below 1, the image is deleted.
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*/
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int refcount() { return refcount_; }
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/** Returns whether this is an original image.
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Images loaded from a file or from memory are marked \p original as
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opposed to images created as a copy of another image with different
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size (width or height).
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\note This is useful for debugging (rarely used in user code).
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\since FLTK 1.4.0
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*/
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int original() { return original_; }
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void release() FL_OVERRIDE;
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virtual void reload();
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Fl_Shared_Image *as_shared_image() FL_OVERRIDE {
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return this;
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}
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Fl_Image *copy(int W, int H) const FL_OVERRIDE;
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Fl_Image *copy() const;
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Fl_Image *copy();
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void color_average(Fl_Color c, float i) FL_OVERRIDE;
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void desaturate() FL_OVERRIDE;
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void draw(int X, int Y, int W, int H, int cx = 0, int cy = 0) FL_OVERRIDE;
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void draw(int X, int Y) { draw(X, Y, w(), h(), 0, 0); }
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void uncache() FL_OVERRIDE;
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static Fl_Shared_Image *find(const char *name, int W = 0, int H = 0);
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static Fl_Shared_Image *get(const char *name, int W = 0, int H = 0);
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static Fl_Shared_Image *get(Fl_RGB_Image *rgb, int own_it = 1);
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static Fl_Shared_Image **images();
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static int num_images();
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static void add_handler(Fl_Shared_Handler f);
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static void remove_handler(Fl_Shared_Handler f);
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/**
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Returns a pointer to the internal Fl_Image object.
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The output is a pointer to the \p internal image ('Fl_Image' or subclass)
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which can be used to inspect or copy the image.
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<b>Do not try to modify the image!</b> You can copy the image though
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if you want or need to change any attributes, size etc. If all you
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need to do is to resize the image you should use
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Fl_Shared_Image::copy(int, int) instead.
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\note The internal image (pointer) is protected for good reasons, e.g.
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to prevent access to the image so it can't be modified by user code.
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\b DO \b NOT cast away the 'const' attribute to modify the image.
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User code should rarely need this method. Use with caution.
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\return const Fl_Image* image, the internal Fl_Image
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\since 1.4.0
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*/
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const Fl_Image *image() const { return image_; }
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}; // class Fl_Shared_Image
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//
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// The following function is provided in the fltk_images library and
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// registers all of the "extra" image file formats that are not part
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// of the core FLTK library...
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//
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FL_EXPORT extern void fl_register_images();
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#endif // !Fl_Shared_Image_H
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