A wxImage cannot (currently) be drawn directly to a \helpref{wxDC}{wxdc}. Instead,
a platform-specific \helpref{wxBitmap}{wxbitmap} object must be created from it using
-the \helpref{wxBitmap::wxBitmap(wxImage,int depth)}{wxbitmapconstr} constructor.
+the \helpref{wxBitmap::wxBitmap(wxImage,int depth)}{wxbitmapctor} constructor.
This bitmap can then
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 wxWidgets 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
\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).}
\latexignore{\rtfignore{\wxheading{Members}}}
-\membersection{wxImage::wxImage}\label{wximageconstr}
+\membersection{wxImage::wxImage}\label{wximagector}
\func{}{wxImage}{\void}
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}}
\wxheading{Remarks}
-Depending on how wxWindows has been configured, not all formats may be available.
+Depending on how wxWidgets has been configured, not all formats may be available.
Note: any handler other than BMP must be previously
initialized with \helpref{wxImage::AddHandler}{wximageaddhandler} or
\perlnote{Constructors supported by wxPerl are:\par
\begin{itemize}
\item{Wx::Image->new( bitmap )}
+\item{Wx::Image->new( icon )}
\item{Wx::Image->new( width, height )}
-\item{Wx::Image->new( name, type )}
-\item{Wx::Image->new( name, mimetype )}
+\item{Wx::Image->new( width, height, data )}
+\item{Wx::Image->new( file, type, index )}
+\item{Wx::Image->new( file, mimetype, index )}
+\item{Wx::Image->new( stream, type, index )}
+\item{Wx::Image->new( stream, mimetype, index )}
\end{itemize}
}
-\membersection{wxImage::\destruct{wxImage}}
+\membersection{wxImage::\destruct{wxImage}}\label{wximagedtor}
\func{}{\destruct{wxImage}}{\void}
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}
+\membersection{wxImage::CleanUpHandlers}\label{wximagecleanuphandlers}
\func{static void}{CleanUpHandlers}{\void}
Deletes all image handlers.
-This function is called by wxWindows on exit.
+This function is called by wxWidgets on exit.
\membersection{wxImage::ComputeHistogram}\label{wximagecomputehistogram}
Returns number of colours in the histogram.
+\membersection{wxImage::ConvertAlphaToMask}\label{wximageconvertalphatomask}
+
+\func{bool}{ConvertAlphaToMask}{\param{unsigned char}{ threshold = 128}}
+
+If the image has alpha channel, this method converts it to mask. All pixels
+with alpha value less than \arg{threshold} are replaced with mask colour
+and the alpha channel is removed. Mask colour is chosen automatically using
+\helpref{FindFirstUnusedColour}{wximagefindfirstunusedcolour}.
+
+If the image image doesn't have alpha channel,
+ConvertAlphaToMask does nothing.
+
+\wxheading{Return value}
+
+\false if FindFirstUnusedColour returns \false, \true otherwise.
+
\membersection{wxImage::ConvertToBitmap}\label{wximageconverttobitmap}
\constfunc{wxBitmap}{ConvertToBitmap}{\void}
-Deprecated, use equivalent \helpref{wxBitmap constructor}{wxbitmapconstr}
+Deprecated, use equivalent \helpref{wxBitmap constructor}{wxbitmapctor}
(which takes wxImage and depth as its arguments) instead.
\membersection{wxImage::ConvertToMono}\label{wxbitmapconverttomono}
\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}
Note that this method involves computing the histogram, which is
computationally intensive operation.
-\membersection{wxImage::FindHandler}
+\membersection{wxImage::FindHandler}\label{wximagefindhandler}
\func{static wxImageHandler*}{FindHandler}{\param{const wxString\& }{name}}
\helpref{wxImageHandler}{wximagehandler}
+\membersection{wxImage::GetImageExtWildcard}\label{wximagegetimageextwildcard}
+
+\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}}
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
-characters in RGBRGBRGB$\ldots$ 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 first pixel of
+the first row, the second one --- to the second pixel of the first row and so
+on until the end of the first row, with second row following after it and so
+on.
You should not delete the returned pointer nor pass it to
\helpref{wxImage::SetData}{wximagesetdata}.
Number of available images. For most image handlers, this is 1 (exceptions
are TIFF and ICO formats).
-\membersection{wxImage::GetHandlers}
+\membersection{wxImage::GetHandlers}\label{wximagegethandlers}
\func{static wxList\&}{GetHandlers}{\void}
\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}
\helpref{wxImage::GetOption}{wximagegetoption},\rtfsp
\helpref{wxImage::GetOptionInt}{wximagegetoptionint}
-\membersection{wxImage::InitStandardHandlers}
+\membersection{wxImage::InitStandardHandlers}\label{wximageinitstandardhandlers}
\func{static void}{InitStandardHandlers}{\void}
Internal use only. Adds standard image format handlers. It only install BMP
for the time being, which is used by wxBitmap.
-This function is called by wxWindows on startup, and shouldn't be called by
+This function is called by wxWidgets on startup, and shouldn't be called by
the user.
\wxheading{See also}
\helpref{wxImageHandler}{wximagehandler},
\helpref{wxInitAllImageHandlers}{wxinitallimagehandlers}
-\membersection{wxImage::InsertHandler}
+\membersection{wxImage::InsertHandler}\label{wximageinserthandler}
\func{static void}{InsertHandler}{\param{wxImageHandler*}{ handler}}
\wxheading{Remarks}
-Depending on how wxWindows has been configured, not all formats may be available.
+Depending on how wxWidgets has been configured, not all formats may be available.
Note: you can use \helpref{GetOptionInt}{wximagegetoptionint} to get the
hotspot for loaded cursor file:
Returns true if image data is present.
-\membersection{wxImage::RemoveHandler}
+\membersection{wxImage::RemoveHandler}\label{wximageremovehandler}
\func{static bool}{RemoveHandler}{\param{const wxString\& }{name}}
\helpref{wxImageHandler}{wximagehandler}
+\membersection{wxImage::Mirror}\label{wximagemirror}
+
+\constfunc{wxImage}{Mirror}{\param{bool}{ horizontally = true}}
+
+Returns a mirrored copy of the image. The parameter {\it horizontally}
+indicates the orientation.
+
+\membersection{wxImage::Replace}\label{wximagereplace}
+
+\func{void}{Replace}{\param{unsigned char}{ r1}, \param{unsigned char}{ g1}, \param{unsigned char}{ b1},
+\param{unsigned char}{ r2}, \param{unsigned char}{ g2}, \param{unsigned char}{ b2}}
+
+Replaces the colour specified by {\it r1,g1,b1} by the colour {\it r2,g2,b2}.
+
+\membersection{wxImage::Rescale}\label{wximagerescale}
+
+\func{wxImage \&}{Rescale}{\param{int}{ width}, \param{int}{ height}}
+
+Changes the size of the image in-place: after a call to this function, the
+image will have the given width and height.
+
+Returns the (modified) image itself.
+
+\wxheading{See also}
+
+\helpref{Scale}{wximagescale}
+
+\membersection{wxImage::Rotate}\label{wximagerotate}
+
+\func{wxImage}{Rotate}{\param{double}{ angle}, \param{const wxPoint\& }{rotationCentre},
+ \param{bool}{ interpolating = true}, \param{wxPoint*}{ offsetAfterRotation = NULL}}
+
+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.
+
+Returns the rotated image, leaving this image intact.
+
+\membersection{wxImage::Rotate90}\label{wximagerotate90}
+
+\constfunc{wxImage}{Rotate90}{\param{bool}{ clockwise = true}}
+
+Returns a copy of the image rotated 90 degrees in the direction
+indicated by {\it clockwise}.
+
\membersection{wxImage::SaveFile}\label{wximagesavefile}
\constfunc{bool}{SaveFile}{\param{const wxString\& }{name}, \param{int}{ type}}
\wxheading{Remarks}
-Depending on how wxWindows has been configured, not all formats may be available.
+Depending on how wxWidgets has been configured, not all formats may be available.
Note: you can use \helpref{GetOptionInt}{wximagegetoptionint} to set the
hotspot before saving an image into a cursor file (default hotspot is in
\end{itemize}
}
-\membersection{wxImage::Mirror}\label{wximagemirror}
-
-\constfunc{wxImage}{Mirror}{\param{bool}{ horizontally = true}}
-
-Returns a mirrored copy of the image. The parameter {\it horizontally}
-indicates the orientation.
-
-\membersection{wxImage::Replace}\label{wximagereplace}
-
-\func{void}{Replace}{\param{unsigned char}{ r1}, \param{unsigned char}{ g1}, \param{unsigned char}{ b1},
-\param{unsigned char}{ r2}, \param{unsigned char}{ g2}, \param{unsigned char}{ b2}}
-
-Replaces the colour specified by {\it r1,g1,b1} by the colour {\it r2,g2,b2}.
-
-\membersection{wxImage::Rescale}\label{wximagerescale}
-
-\func{wxImage \&}{Rescale}{\param{int}{ width}, \param{int}{ height}}
-
-Changes the size of the image in-place: after a call to this function, the
-image will have the given width and height.
-
-Returns the (modified) image itself.
-
-\wxheading{See also}
-
-\helpref{Scale}{wximagescale}
-
-\membersection{wxImage::Rotate}\label{wximagerotate}
-
-\func{wxImage}{Rotate}{\param{double}{ angle}, \param{const wxPoint\& }{rotationCentre},
- \param{bool}{ interpolating = true}, \param{wxPoint*}{ offsetAfterRotation = NULL}}
-
-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.
-
-Returns the rotated image, leaving this image intact.
-
-\membersection{wxImage::Rotate90}\label{wximagerotate90}
-
-\constfunc{wxImage}{Rotate90}{\param{bool}{ clockwise = true}}
-
-Returns a copy of the image rotated 90 degrees in the direction
-indicated by {\it clockwise}.
-
\membersection{wxImage::Scale}\label{wximagescale}
\constfunc{wxImage}{Scale}{\param{int}{ width}, \param{int}{ height}}
// 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:
\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}}
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 malloc(), NOT with operator new.
+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.
\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).
be set directly. In that case you will have to get access to the image data
using the \helpref{GetData}{wximagegetdata} method.
-\membersection{wxImage::operator $=$}
+\membersection{wxImage::operator $=$}\label{wximageassign}
\func{wxImage\& }{operator $=$}{\param{const wxImage\& }{image}}
Returns 'this' object.
-\membersection{wxImage::operator $==$}
+\membersection{wxImage::operator $==$}\label{wximageequal}
\constfunc{bool}{operator $==$}{\param{const wxImage\& }{image}}
Returns true if the images were effectively equal, false otherwise.
-\membersection{wxImage::operator $!=$}
+\membersection{wxImage::operator $!=$}\label{wximagenotequal}
\constfunc{bool}{operator $!=$}{\param{const wxImage\& }{image}}
This software is based in part on the work of the Independent JPEG Group.
-(Applies when wxWindows is linked with JPEG support. wxJPEGHandler uses libjpeg
+(Applies when wxWidgets is linked with JPEG support. wxJPEGHandler uses libjpeg
created by IJG.)
\wxheading{Derived from}
\latexignore{\rtfignore{\wxheading{Members}}}
-\membersection{wxImageHandler::wxImageHandler}\label{wximagehandlerconstr}
+\membersection{wxImageHandler::wxImageHandler}\label{wximagehandlerctor}
\func{}{wxImageHandler}{\void}
Default constructor. In your own default constructor, initialise the members
m\_name, m\_extension and m\_type.
-\membersection{wxImageHandler::\destruct{wxImageHandler}}
+\membersection{wxImageHandler::\destruct{wxImageHandler}}\label{wximagehandlerdtor}
\func{}{\destruct{wxImageHandler}}{\void}
Destroys the wxImageHandler object.
-\membersection{wxImageHandler::GetName}
+\membersection{wxImageHandler::GetName}\label{wximagehandlergetname}
\constfunc{wxString}{GetName}{\void}
Gets the name of this handler.
-\membersection{wxImageHandler::GetExtension}
+\membersection{wxImageHandler::GetExtension}\label{wximagehandlergetextension}
\constfunc{wxString}{GetExtension}{\void}
Number of available images. For most image handlers, this is 1 (exceptions
are TIFF and ICO formats).
-\membersection{wxImageHandler::GetType}
+\membersection{wxImageHandler::GetType}\label{wximagehandlergettype}
\constfunc{long}{GetType}{\void}
Gets the image type associated with this handler.
-\membersection{wxImageHandler::GetMimeType}
+\membersection{wxImageHandler::GetMimeType}\label{wximagehandlergetmimetype}
\constfunc{wxString}{GetMimeType}{\void}
\helpref{wxImage::SaveFile}{wximagesavefile},
\helpref{wxImageHandler::LoadFile}{wximagehandlerloadfile}
-\membersection{wxImageHandler::SetName}
+\membersection{wxImageHandler::SetName}\label{wximagehandlersetname}
\func{void}{SetName}{\param{const wxString\& }{name}}
\docparam{name}{Handler name.}
-\membersection{wxImageHandler::SetExtension}
+\membersection{wxImageHandler::SetExtension}\label{wximagehandlersetextension}
\func{void}{SetExtension}{\param{const wxString\& }{extension}}
\docparam{mimename}{Handler MIME type.}
-\membersection{wxImageHandler::SetType}
+\membersection{wxImageHandler::SetType}\label{wximagehandlersettype}
\func{void}{SetType}{\param{long }{type}}
projects / wxWidgets.git / blobdiff