143 lines
5.6 KiB
HTML
143 lines
5.6 KiB
HTML
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<head><title>Fl_Image</title></head><body bgcolor=white>
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<h1>class Fl_Image</h1>
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This class holds an image, normally used to label a widget. The
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subclasses define how the data is interpreted, and usually store
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server-side cached versions of the image. All the current types
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define pixel arrays, but other types of images, such as vector
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graphics, can be defined.
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<h2>Methods</h2>
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<h4>ulong id, mask;<br>
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void _draw(int X, int Y, int W, int H, int cx, int cy);</h4>
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Subclasses may use these <i>protected</i> members of the base class to
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draw a cached pixel array. They must first set <tt>id</tt> and
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<tt>mask</tt> to the color and transparency offscreen windows, using
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system-specific code. Then they can call <tt>_draw()</tt> to draw
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them.
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<h4>int w,h</h4>
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These members hold the width and height of the image. They are not
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correct until <tt>measure()</tt> is called. These are public instance
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variables for back comptability, but you should never set them.
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<h4>virtual void Fl_Image::measure(int W, int H);</h4>
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Measure how big the image will be if it is drawn inside a W,H
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rectangle and put the result into w,h. For most image types this does
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nothing and w,h are set by the constructor. This may be used to
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initialize the scaling for variable-sized images.
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<h4>virtual void Fl_Image::draw(int x,int y,int w,int h, int cx,int
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cy);</h4>
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Draw the image so the point <i>cx,cy</i> of the image is at
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<i>x,y</i>. The image may be scaled or clipped to fit in the <i>w,h</i>
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rectangle, but this is not necessary (although obeying the current
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fl_clip value is!).
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<h4>void Fl_Image::draw(int x,int y,int w,int h, Fl_Flags align);</h4>
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This <i>non-virtual</i> function uses <tt>measure()</tt> and the
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<i>align</i> flags to figure out <i>cx,cy</i> and call the normal draw
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function. This allows you to center or align any edge of the image
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with a bounding box.
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<h4>virtual Fl_Image::~Fl_Image();</h4>
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The destructor throws away any server-cached information, but in most
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cases does not destroy the local data passed to a constructor.
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<H2><A name=Fl_Bitmap>class Fl_Bitmap : public Fl_Image</A></H2>
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This object encapsulates the width, height, and bits of an X bitmap
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(XBM), and allows you to make an <TT>Fl_Widget</TT> use a bitmap as a
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label, or to just draw the bitmap directly.
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<H4>Fl_Bitmap(const char *bits, int W, int H)
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<BR> Fl_Bitmap(const uchar *bits, int W, int H)</H4>
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Construct using an X bitmap. The bits pointer is simply copied to the
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object, so it must point at persistent storage. The two constructors
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are provided because various X implementations disagree about the type
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of bitmap data. To use an XBM file use:
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<UL>
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<PRE>
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#include "foo.xbm"
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...
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Fl_Bitmap bitmap = new Fl_Bitmap(foo_bits, foo_width, foo_height);
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</PRE>
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</UL>
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<H4>~Fl_Bitmap()</H4>
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The destructor will destroy any X pixmap created. It does not do
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anything to the bits data.
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<H4>void draw(int x, int y, int w, int h, int ox = 0, int oy = 0)</H4>
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1 bits are drawn with the current color, 0 bits
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are unchanged.
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The image is clipped to the destination rectangle: the area
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<TT>ox,oy,w,h</TT> is copied to <TT>x,y,w,h</TT>.
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<H4>void draw(int x, int y)</H4>
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Draws the bitmap with the upper-left corner at <TT>x,y</TT>. This is
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the same as doing <TT>draw(x,y,this->w,this->h,0,0)</TT>.
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<H2><A name=Fl_Pixmap>class Fl_Pixmap : public Fl_Image</A></H2>
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This object encapsulates the data from an XPM image, and allows you to
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make an <TT>Fl_Widget</TT> use a pixmap as a label, or to just draw
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the pixmap directly.
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<H4>Fl_Pixmap(char *const* data)</H4>
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Construct using XPM data. The data pointer is simply copied to the
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object, so it must point at persistent storage. To use an XPM file do:
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<UL>
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<PRE>
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#include <fltk/Fl_Pixmap.h>
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#include "foo.xpm"
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...
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Fl_Pixmap pixmap = new Fl_Pixmap(foo);
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</PRE>
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</UL>
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<H4>~Fl_Pixmap()</H4>
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The destructor will destroy any X pixmap created. It does not do
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anything to the data.
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<H4>void draw(int x, int y, int w, int h, int ox = 0, int oy = 0)</H4>
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The image is clipped to the destination rectangle: the area
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<TT>ox,oy,w,h</TT> is copied to <TT>x,y,w,h</TT>. The current
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implementation converts the pixmap to 24-bit RGB data and uses <A
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href=#fl_draw_image><TT>fl_draw_image()</TT></A> to draw it. Thus you
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will get dithered colors on an 8 bit screen. </P>
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<H4>void draw(int x, int y)</H4>
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Draws the image with the upper-left corner at <TT>x,y</TT>. This is
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the same as doing <TT>draw(x,y,this->w,this->h,0,0)</TT>.
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<H2><A name=Fl_RGB_Image>class Fl_RGB_Image</A></H2>
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This object encapsulates a full-color RGB image, and allows you to
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make an <TT>Fl_Widget</TT> use an image as a label, or to just draw the
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image directly.
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<H4>Fl_RGB_Image(const uchar *data, int W, int H, int D = 3, int LD = 0)</H4>
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Construct using a pointer to RGB data. <TT>W</TT> and <TT>H</TT> are
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the size of the image in pixels. <TT>D</TT> is the delta between pixels
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(it may be more than 3 to skip alpha or other data, or negative to flip
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the image left/right). <TT>LD</TT> is the delta between lines (it may
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be more than <TT>D * W</TT> to crop images, or negative to flip the
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image vertically). The data pointer is simply copied to the object, so
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it must point at persistent storage.
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<H4>~Fl_RGB_Image()</H4>
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The destructor will destroy any X pixmap created. It does not do
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anything to the data.
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<H4>void draw(int x, int y, int w, int h, int ox = 0, int oy = 0)</H4>
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The image is clipped to the destination rectangle: the area
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<TT>ox,oy,w,h</TT> is copied to <TT>x,y,w,h</TT>.
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<H4>void draw(int x, int y)</H4>
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Draws the image with the upper-left corner at <TT>x,y</TT>. This is
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the same as doing <TT>draw(x,y,this->w,this->h,0,0)</TT>.
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</body></html>
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