X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/4fa0a5b44341885a0886f2ae6723d2441bd1f62f..e21011866e9a89b5abda727f80e666ed2d7041c7:/docs/latex/wx/image.tex

diff --git a/docs/latex/wx/image.tex b/docs/latex/wx/image.tex
index 574391e7c1..378663ced1 100644
--- a/docs/latex/wx/image.tex
+++ b/docs/latex/wx/image.tex
@@ -15,17 +15,33 @@ be drawn in a device context, using \helpref{wxDC::DrawBitmap}{wxdcdrawbitmap}.
 One colour value of the image may be used as a mask colour which will lead to the automatic
 creation of a \helpref{wxMask}{wxmask} object associated to the bitmap object.
 
+\wxheading{Alpha channel support}
+
+Starting from wxWindows 2.5.0 wxImage supports alpha channel data, that is in
+addition to a byte for the red, green and blue colour components for each pixel
+it also stores a byte representing the pixel opacity. The alpha value of $0$
+corresponds to a transparent pixel (null opacity) while the value of $255$
+means that the pixel is 100\% opaque.
+
+Unlike the RGB data, not all images have the alpha channel and before using 
+\helpref{GetAlpha}{wximagegetalpha} you should check if this image contains
+alpha value with \helpref{HasAlpha}{wximagehasalpha}. In fact, currently only
+images loaded from PNG files with transparency information will have alpha
+channel but support for it will be added to the other formats as well (as well
+as support for saving images with alpha channel which is not still implemented
+either).
+
 \wxheading{Available image handlers}
 
 The following image handlers are available. {\bf wxBMPHandler} is always
-installed by default. To use other image formats, install the appropiate
+installed by default. To use other image formats, install the appropriate
 handler with \helpref{wxImage::AddHandler}{wximageaddhandler} or 
 \helpref{wxInitAllImageHandlers}{wxinitallimagehandlers}.
 
 \twocolwidtha{5cm}%
 \begin{twocollist}
 \twocolitem{\indexit{wxBMPHandler}}{For loading and saving, always installed.}
-\twocolitem{\indexit{wxPNGHandler}}{For loading and saving.}
+\twocolitem{\indexit{wxPNGHandler}}{For loading (including alpha support) and saving.}
 \twocolitem{\indexit{wxJPEGHandler}}{For loading and saving.}
 \twocolitem{\indexit{wxGIFHandler}}{Only for loading, due to legal issues.}
 \twocolitem{\indexit{wxPCXHandler}}{For loading and saving (see below).}
@@ -77,14 +93,15 @@ instead.) Constructs an image from a platform-dependent bitmap. This preserves
 mask information so that bitmaps and images can be converted back
 and forth without loss in that respect.
 
-\func{}{wxImage}{\param{int}{ width}, \param{int}{ height}}
+\func{}{wxImage}{\param{int}{ width}, \param{int}{ height}, \param{bool}{ clear=true}}
 
-Creates an image with the given width and height.
+Creates an image with the given width and height.  If {\it clear} is true, the new image will be initialized to black.
+Otherwise, the image data will be uninitialized.
 
-\func{}{wxImage}{\param{int}{ width}, \param{int}{ height}, \param{unsigned char*}{ data}, \param{bool}{ static\_data=FALSE}}
+\func{}{wxImage}{\param{int}{ width}, \param{int}{ height}, \param{unsigned char*}{ data}, \param{bool}{ static\_data=false}}
 
 Creates an image from given data with the given width and height. If 
-{\it static\_data} is TRUE, then wxImage will not delete the actual
+{\it static\_data} is true, then wxImage will not delete the actual
 image data in its destructor, otherwise it will free it by calling
 {\it free()}.
 
@@ -199,7 +216,7 @@ of a given handler class in an application session.}
 
 \func{bool}{CanRead}{\param{const wxString\&}{ filename}}
 
-returns TRUE if the current image handlers can read this file
+returns true if the current image handlers can read this file
 
 \pythonnote{In wxPython this static method is named {\tt wxImage\_AddHandler}.}
 \membersection{wxImage::CleanUpHandlers}
@@ -259,9 +276,10 @@ Returns an identical copy of the image.
 
 \membersection{wxImage::Create}\label{wximagecreate}
 
-\func{bool}{Create}{\param{int}{ width}, \param{int}{ height}}
+\func{bool}{Create}{\param{int}{ width}, \param{int}{ height}, \param{bool}{ clear=true}}
 
-Creates a fresh image.
+Creates a fresh image.  If {\it clear} is true, the new image will be initialized to black.
+Otherwise, the image data will be uninitialized.
 
 \wxheading{Parameters}
 
@@ -271,7 +289,7 @@ Creates a fresh image.
 
 \wxheading{Return value}
 
-TRUE if the call succeeded, FALSE otherwise.
+true if the call succeeded, false otherwise.
 
 \membersection{wxImage::Destroy}\label{wximagedestroy}
 
@@ -296,7 +314,7 @@ order) by 1 until an unused colour is found or the colour space exhausted.
 
 \wxheading{Return value}
 
-Returns FALSE if there is no unused colour left, TRUE on success.
+Returns false if there is no unused colour left, true on success.
 
 \wxheading{Notes}
 
@@ -337,6 +355,48 @@ A pointer to the handler if found, NULL otherwise.
 
 \helpref{wxImageHandler}{wximagehandler}
 
+\membersection{wxImage::GetImageExtWildcard}
+
+\func{static wxString}{GetImageExtWildcard}{\void}
+
+Iterates all registered wxImageHandler objects, and returns a string containing file extension masks
+suitable for passing to file open/save dialog boxes.
+
+\wxheading{Return value}
+
+The format of the returned string is "(*.ext1;*.ext2)|*.ext1;*.ext2".
+
+It is usually a good idea to prepend a description before passing the result to the dialog.
+
+Example:
+
+\begin{verbatim}
+    wxFileDialog FileDlg( this, "Choose Image", ::wxGetWorkingDirectory(), "", _("Image Files ") + wxImage::GetImageExtWildcard(), wxOPEN );
+\end{verbatim}
+
+\wxheading{See also}
+
+\helpref{wxImageHandler}{wximagehandler}
+
+\membersection{wxImage::GetAlpha}\label{wximagegetalpha}
+
+\constfunc{unsigned char}{GetAlpha}{\param{int}{ x}, \param{int}{ y}}
+
+Returns the alpha value for the given pixel. This function may only be called
+for the images with alpha channel, use \helpref{HasAlpha}{wximagehasalpha} to
+check for this.
+
+The returned value is the {\it opacity} of the image, i.e. the value of $0$
+corresponds to the transparent pixels while the value of $255$ -- to the opaque
+ones.
+
+\constfunc{unsigned char *}{GetAlpha}{\void}
+
+Returns pointer to the array storing the alpha values for this image. This
+pointer is {\tt NULL} for the images without the alpha channel. If the image
+does have it, this pointer may be used to directly manipulate the alpha values
+which are stored as the \helpref{RGB}{wximagegetdata} ones.
+
 \membersection{wxImage::GetBlue}\label{wximagegetblue}
 
 \constfunc{unsigned char}{GetBlue}{\param{int}{ x}, \param{int}{ y}}
@@ -349,7 +409,12 @@ Returns the blue intensity at the given coordinate.
 
 Returns the image data as an array. This is most often used when doing
 direct image manipulation. The return value points to an array of
-chararcters in RGBGBRGB... format.
+characters in RGBRGBRGB$\ldots$ format in the top-to-bottom, left-to-right
+order, that is the first RGB triplet corresponds to the pixel $(0, 0)$, the
+second one --- to $(0, 1)$ and so on.
+
+You should not delete the returned pointer nor pass it to
+\helpref{wxImage::SetData}{wximagesetdata}.
 
 \membersection{wxImage::GetGreen}\label{wximagegetgreen}
 
@@ -394,12 +459,6 @@ available images.
 Number of available images. For most image handlers, this is 1 (exceptions
 are TIFF and ICO formats).
 
-\membersection{wxImage::GetRed}\label{wximagegetred}
-
-\constfunc{unsigned char}{GetRed}{\param{int}{ x}, \param{int}{ y}}
-
-Returns the red intensity at the given coordinate.
-
 \membersection{wxImage::GetHandlers}
 
 \func{static wxList\&}{GetHandlers}{\void}
@@ -443,6 +502,12 @@ used when converting to wxBitmap under Windows.
 
 Eventually wxImage handlers will set the palette if one exists in the image file.
 
+\membersection{wxImage::GetRed}\label{wximagegetred}
+
+\constfunc{unsigned char}{GetRed}{\param{int}{ x}, \param{int}{ y}}
+
+Returns the red intensity at the given coordinate.
+
 \membersection{wxImage::GetSubImage}\label{wximagegetsubimage}
 
 \constfunc{wxImage}{GetSubImage}{\param{const wxRect\&}{ rect}}
@@ -460,11 +525,21 @@ Gets the width of the image in pixels.
 
 \helpref{wxImage::GetHeight}{wximagegetheight}
 
+\membersection{wxImage::HasAlpha}\label{wximagehasalpha}
+
+\constfunc{bool}{HasAlpha}{\void}
+
+Returns true if this image has alpha channel, false otherwise.
+
+\wxheading{See also}
+
+\helpref{GetAlpha}{wximagegetalpha}, \helpref{SetAlpha}{wximagesetalpha}
+
 \membersection{wxImage::HasMask}\label{wximagehasmask}
 
 \constfunc{bool}{HasMask}{\void}
 
-Returns TRUE if there is a mask active, FALSE otherwise.
+Returns true if there is a mask active, false otherwise.
 
 \membersection{wxImage::GetOption}\label{wximagegetoption}
 
@@ -497,7 +572,7 @@ Gets a user-defined option as an integer. The function is case-insensitive to {\
 
 \constfunc{bool}{HasOption}{\param{const wxString\&}{ name}}
 
-Returns TRUE if the given option is present. The function is case-insensitive to {\it name}.
+Returns true if the given option is present. The function is case-insensitive to {\it name}.
 
 \wxheading{See also}
 
@@ -593,8 +668,8 @@ hotspot for loaded cursor file:
 
 \wxheading{Return value}
 
-TRUE if the operation succeeded, FALSE otherwise. If the optional index parameter is out of range,
-FALSE is returned and a call to wxLogError() takes place.
+true if the operation succeeded, false otherwise. If the optional index parameter is out of range,
+false is returned and a call to wxLogError() takes place.
 
 \wxheading{See also}
 
@@ -622,7 +697,7 @@ mimetype from a file}
 
 \constfunc{bool}{Ok}{\void}
 
-Returns TRUE if image data is present.
+Returns true if image data is present.
 
 \membersection{wxImage::RemoveHandler}
 
@@ -635,7 +710,7 @@ is not deleted.
 
 \wxheading{Return value}
 
-TRUE if the handler was found and removed, FALSE otherwise.
+true if the handler was found and removed, false otherwise.
 
 \wxheading{See also}
 
@@ -686,7 +761,7 @@ Saves an image in the given stream.
 
 \wxheading{Return value}
 
-TRUE if the operation succeeded, FALSE otherwise.
+true if the operation succeeded, false otherwise.
 
 \wxheading{Remarks}
 
@@ -724,7 +799,7 @@ mimetype to the named file}
 
 \membersection{wxImage::Mirror}\label{wximagemirror}
 
-\constfunc{wxImage}{Mirror}{\param{bool}{ horizontally = TRUE}}
+\constfunc{wxImage}{Mirror}{\param{bool}{ horizontally = true}}
 
 Returns a mirrored copy of the image. The parameter {\it horizontally}
 indicates the orientation.
@@ -752,9 +827,9 @@ Returns the (modified) image itself.
 \membersection{wxImage::Rotate}\label{wximagerotate}
 
 \func{wxImage}{Rotate}{\param{double}{ angle}, \param{const wxPoint\& }{rotationCentre},
- \param{bool}{ interpolating = TRUE}, \param{wxPoint*}{ offsetAfterRotation = NULL}}
+ \param{bool}{ interpolating = true}, \param{wxPoint*}{ offsetAfterRotation = NULL}}
 
-Rotates the image about the given point, by {\it angle} radians. Passing TRUE
+Rotates the image about the given point, by {\it angle} radians. Passing true
 to {\it interpolating} results in better image quality, but is slower. If the
 image has a mask, then the mask colour is used for the uncovered pixels in the
 rotated image background. Else, black (rgb 0, 0, 0) will be used.
@@ -763,7 +838,7 @@ Returns the rotated image, leaving this image intact.
 
 \membersection{wxImage::Rotate90}\label{wximagerotate90}
 
-\constfunc{wxImage}{Rotate90}{\param{bool}{ clockwise = TRUE}}
+\constfunc{wxImage}{Rotate90}{\param{bool}{ clockwise = true}}
 
 Returns a copy of the image rotated 90 degrees in the direction
 indicated by {\it clockwise}.
@@ -788,7 +863,7 @@ Example:
     // rescale it to have size of 32*32
     if ( bmp.GetWidth() != 32 || bmp.GetHeight() != 32 )
     {
-        wxImage image(bmp);
+        wxImage image = bmp.ConvertToImage();
         bmp = wxBitmap(image.Scale(32, 32));
 
         // another possibility:
@@ -802,6 +877,23 @@ Example:
 
 \helpref{Rescale}{wximagerescale}
 
+\membersection{wxImage::SetAlpha}\label{wximagesetalpha}
+
+\func{void}{SetAlpha}{\param{unsigned char *}{alpha = {\tt NULL}}}
+
+This function is similar to \helpref{SetData}{wximagesetdata} and has similar
+restrictions. The pointer passed to it may however be {\tt NULL} in which case
+the function will allocate the alpha array internally -- this is useful to add
+alpha channel data to an image which doesn't have any. If the pointer is not 
+{\tt NULL}, it must have one byte for each image pixel and be allocated with 
+{\tt malloc()}. wxImage takes ownership of the pointer and will free it.
+
+\func{void}{SetAlpha}{\param{int }{x}, \param{int }{y}, \param{unsigned char }{alpha}}
+
+Sets the alpha value for the given pixel. This function should only be called
+if the image has alpha channel data, use \helpref{HasAlpha}{wximagehasalpha} to
+check for this.
+
 \membersection{wxImage::SetData}\label{wximagesetdata}
 
 \func{void}{SetData}{\param{unsigned char*}{data}}
@@ -810,15 +902,23 @@ Sets the image data without performing checks. The data given must have
 the size (width*height*3) or results will be unexpected. Don't use this
 method if you aren't sure you know what you are doing.
 
+The data must have been allocated with {\tt malloc()}, {\large {\bf NOT}} with
+{\tt operator new}.
+
+After this call the pointer to the data is owned by the wxImage object,
+that will be responsible for deleting it.
+Do not pass to this function a pointer obtained through
+\helpref{wxImage::GetData}{wximagegetdata}.
+
 \membersection{wxImage::SetMask}\label{wximagesetmask}
 
-\func{void}{SetMask}{\param{bool}{ hasMask = TRUE}}
+\func{void}{SetMask}{\param{bool}{ hasMask = true}}
 
 Specifies whether there is a mask or not. The area of the mask is determined by the current mask colour.
 
 \membersection{wxImage::SetMaskColour}\label{wximagesetmaskcolour}
 
-\func{void}{SetMaskColour}{\param{unsigned char }{red}, \param{unsigned char }{blue}, \param{unsigned char }{green}}
+\func{void}{SetMaskColour}{\param{unsigned char }{red}, \param{unsigned char }{green}, \param{unsigned char }{blue}}
 
 Sets the mask colour for this image (and tells the image to use the mask).
 
@@ -840,8 +940,8 @@ in {\it mask} has given RGB value.
 
 \wxheading{Return value}
 
-Returns FALSE if {\it mask} does not have same dimensions as the image or if
-there is no unused colour left. Returns TRUE if the mask was successfully 
+Returns false if {\it mask} does not have same dimensions as the image or if
+there is no unused colour left. Returns true if the mask was successfully 
 applied.
 
 \wxheading{Notes}
@@ -901,7 +1001,7 @@ Returns 'this' object.
 
 \membersection{wxImage::operator $==$}
 
-\func{bool}{operator $==$}{\param{const wxImage\& }{image}}
+\constfunc{bool}{operator $==$}{\param{const wxImage\& }{image}}
 
 Equality operator. This operator tests whether the internal data pointers are
 equal (a fast test).
@@ -912,11 +1012,11 @@ equal (a fast test).
 
 \wxheading{Return value}
 
-Returns TRUE if the images were effectively equal, FALSE otherwise.
+Returns true if the images were effectively equal, false otherwise.
 
 \membersection{wxImage::operator $!=$}
 
-\func{bool}{operator $!=$}{\param{const wxImage\& }{image}}
+\constfunc{bool}{operator $!=$}{\param{const wxImage\& }{image}}
 
 Inequality operator. This operator tests whether the internal data pointers are
 unequal (a fast test).
@@ -927,7 +1027,7 @@ unequal (a fast test).
 
 \wxheading{Return value}
 
-Returns TRUE if the images were unequal, FALSE otherwise.
+Returns true if the images were unequal, false otherwise.
 
 \section{\class{wxImageHandler}}\label{wximagehandler}
 
@@ -1014,7 +1114,7 @@ Gets the MIME type associated with this handler.
 
 \membersection{wxImageHandler::LoadFile}\label{wximagehandlerloadfile}
 
-\func{bool}{LoadFile}{\param{wxImage* }{image}, \param{wxInputStream\&}{ stream}, \param{bool}{ verbose=TRUE}, \param{int}{ index=0}}
+\func{bool}{LoadFile}{\param{wxImage* }{image}, \param{wxInputStream\&}{ stream}, \param{bool}{ verbose=true}, \param{int}{ index=0}}
 
 Loads a image from a stream, putting the resulting data into {\it image}. If the image file contains
 more than one image and the image handler is capable of retrieving these individually, {\it index}
@@ -1026,13 +1126,13 @@ indicates which image to read from the stream.
 
 \docparam{stream}{Opened input stream for reading image data.}
 
-\docparam{verbose}{If set to TRUE, errors reported by the image handler will produce wxLogMessages.}
+\docparam{verbose}{If set to true, errors reported by the image handler will produce wxLogMessages.}
 
 \docparam{index}{The index of the image in the file (starting from zero).}
 
 \wxheading{Return value}
 
-TRUE if the operation succeeded, FALSE otherwise.
+true if the operation succeeded, false otherwise.
 
 \wxheading{See also}
 
@@ -1054,7 +1154,7 @@ Saves a image in the output stream.
 
 \wxheading{Return value}
 
-TRUE if the operation succeeded, FALSE otherwise.
+true if the operation succeeded, false otherwise.
 
 \wxheading{See also}
 
