class Fl_Image

Class Hierarchy

Include Files

Description

Fl_Image is the base class used for caching and drawing all kinds of images in FLTK. This class keeps track of common image data such as the pixels, colormap, width, height, and depth. Virtual methods are used to provide type-specific image handling.

Since the Fl_Image class does not support image drawing by itself, calling the draw() method results in a box with an X in it being drawn instead.

Methods

Fl_Image(int W, int H, int D);

The constructor creates an empty image with the specified width, height, and depth. The width and height are in pixels. The depth is 0 for bitmaps, 1 for pixmap (colormap) images, and 1 to 4 for color images.

virtual ~Fl_Image();

The destructor is a virtual method that frees all memory used by the image.

virtual void color_average(Fl_Color c, float i);

The color_average() method averages the colors in the image with the FLTK color value c. The i argument specifies the amount of the original image to combine with the color, so a value of 1.0 results in no color blend, and a value of 0.0 results in a constant image of the specified color. The original image data is not altered by this method.

virtual Fl_Image *copy(int W, int H);
copy();

The copy() method creates a copy of the specified image. If the width and height are provided, the image is resized to the specified size.

int count();

The count() method returns the number of data values associated with the image. The value will be 0 for images with no associated data, 1 for bitmap and color images, and greater than 2 for pixmap images.

int d();
protected void d(int D);

The first form of the d() method returns the current image depth. The return value will be 0 for bitmaps, 1 for pixmaps, and 1 to 4 for color images.

The second form is a protected method that sets the current image depth.

const char * const *data();
protected void data(const char * const *data, int count);

The first form of the data() method returns a pointer to the current image data array. Use the count() method to find the size of the data array.

The second form is a protected method that sets the current array pointer and count of pointers in the array.

virtual void desaturate()

The desaturate() method converts an image to grayscale. If the image contains an alpha channel (depth = 4), the alpha channel is preserved. This method does not alter the original image data.

void draw(int X, int Y);
virtual void draw(int X, int Y, int W, int H, int cx, int cy);

The draw() methods draw the image. The first form specifies the upper-lefthand corner of the image. The second form specifies a bounding box for the image, with the origin (upper-lefthand corner) of the image offset by the cx and cy arguments.

protected void draw_empty(int X, int Y);

The protected method draw_empty() draws a box with an X in it. It can be used to draw any image that lacks image data.

int h();
protected void h(int H);

The first form of the h() method returns the current image height in pixels.

The second form is a protected method that sets the current image height.

void inactive();

The inactive() method calls color_average(FL_GRAY, 0.33f) to produce an image that appears grayed out. This method does not alter the original image data.

virtual void label(Fl_Widget *w); virtual void label(Fl_Menu_Item *m);

The label() methods are an obsolete way to set the image attribute of a widget or menu item. Use the image() or deimage() methods of the Fl_Widget and Fl_Menu_Item classes instead.

int ld();
protected void ld(int LD);

The first form of the ld() method returns the current line data size in bytes. Line data is extra data that is included after each line of color image data and is normally not present.

The second form is a protected method that sets the current line data size in bytes.

int w();
protected void w(int W);

The first form of the w() method returns the current image width in pixels.

The second form is a protected method that sets the current image width.