wxWidgets/interface/wx/imaglist.h
Vadim Zeitlin 6feeed9fe9 Handle transparency to the best of our ability in wxImageList
Don't take the value of "mask" parameter of wxImageList constructor too
prescriptively, it predates support for alpha in wxWidgets by many years
and was never meant to actually suppress using it.

Instead, do the best thing we can in all cases, i.e. use alpha if it's
specified and supported and use mask otherwise. But only create the mask
from light grey colour if we have nothing else if "mask" is true in
wxImageList constructor, as this is a potentially destructive action
that must not be performed if the user has explicitly decided to set
this parameter to false.

Incidentally fix handling of alpha with comctl32.dll v5 (which is used
in the absence of any manifest) by converting it to a mask in this case:
this is not ideal, but better than just using black background as it
happened before, and restores pre-3.1.5 behaviour.

Also simplify the generic version which just has to create the default
mask if necessary and doesn't have to do anything at all in all the
other cases.

Note that these changes required relaxing some of the existing unit
tests as wxMSW implementation now can add alpha channel to the bitmaps
that didn't have it -- but this is a more useful behaviour, and so it
makes more sense to adapt the tests to it rather than doing a less
useful thing just to conform to the tests.

This commit is best viewed with git --color-moved
--color-moved-ws=ignore-all-spac options.

Closes #22349.
2022-05-06 02:12:54 +01:00

263 lines
8.1 KiB
Objective-C

/////////////////////////////////////////////////////////////////////////////
// Name: imaglist.h
// Purpose: interface of wxImageList
// Author: wxWidgets team
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/**
Flag values for Set/GetImageList
*/
enum
{
wxIMAGE_LIST_NORMAL, // Normal icons
wxIMAGE_LIST_SMALL, // Small icons
wxIMAGE_LIST_STATE // State icons: unimplemented (see WIN32 documentation)
};
/**
Flags for Draw
*/
#define wxIMAGELIST_DRAW_NORMAL 0x0001
#define wxIMAGELIST_DRAW_TRANSPARENT 0x0002
#define wxIMAGELIST_DRAW_SELECTED 0x0004
#define wxIMAGELIST_DRAW_FOCUSED 0x0008
/**
@class wxImageList
A wxImageList contains a list of images, which are stored in an unspecified
form. Images can use alpha channel or masks for transparent drawing, and
can be made from a variety of sources including bitmaps and icons.
wxImageList is used principally in conjunction with wxTreeCtrl and
wxListCtrl classes.
Use of this class is not recommended in the new code as it doesn't support
showing DPI-dependent bitmaps. Please use wxWithImages::SetImages() instead
of wxWithImages::SetImageList().
@library{wxcore}
@category{gdi}
@see wxTreeCtrl, wxListCtrl
*/
class wxImageList : public wxObject
{
public:
/**
Default ctor.
*/
wxImageList();
/**
Constructor specifying the image size, whether image masks should be created,
and the initial size of the list.
Note that the size is specified in logical pixels.
@param width
Width of the images in the list.
@param height
Height of the images in the list.
@param mask
If @true, all images will have masks, with the mask being created
from the light grey pixels if not specified otherwise, i.e. if the
image doesn't have neither alpha channel nor mask and no mask is
explicitly specified when adding it. Note that if an image does
have alpha channel or mask, it will always be used, whether this
parameter is @true or @false.
@param initialCount
The initial size of the list.
@see Create()
*/
wxImageList(int width, int height, bool mask = true,
int initialCount = 1);
/**
Adds a new image or images using a bitmap and optional mask bitmap.
The logical size of the bitmap should be the same as the size specified
when constructing wxImageList. If the logical width of the bitmap is
greater than the image list width, bitmap is split into smaller images
of the required width.
@param bitmap
Bitmap representing the opaque areas of the image.
@param mask
Monochrome mask bitmap, representing the transparent areas of the image.
@return The new zero-based image index.
*/
int Add(const wxBitmap& bitmap,
const wxBitmap& mask = wxNullBitmap);
/**
Adds a new image or images using a bitmap and mask colour.
The logical size of the bitmap should be the same as the size specified
when constructing wxImageList. If the logical width of the bitmap is
greater than the image list width, bitmap is split into smaller images
of the required width.
@param bitmap
Bitmap representing the opaque areas of the image.
@param maskColour
Colour indicating which parts of the image are transparent.
@return The new zero-based image index.
*/
int Add(const wxBitmap& bitmap, const wxColour& maskColour);
/**
Adds a new image using an icon.
The logical size of the icon should be the same as the size specified
when constructing wxImageList.
@param icon
Icon to use as the image.
@return The new zero-based image index.
@onlyfor{wxmsw,wxosx}
*/
int Add(const wxIcon& icon);
/**
Initializes the list.
See wxImageList() for details.
This function can be called only once after creating the object using
its default ctor or after calling Destroy().
*/
bool Create(int width, int height, bool mask = true,
int initialCount = 1);
/**
Destroys the current list.
This function resets the object to its initial state and does more than
just RemoveAll() in the native wxMSW version.
After calling it, Create() may be called again to recreate the image
list, e.g. using a different size.
@since 3.1.6
*/
void Destroy();
/**
Draws a specified image onto a device context.
@param index
Image index, starting from zero.
@param dc
Device context to draw on.
@param x
X position on the device context.
@param y
Y position on the device context.
@param flags
How to draw the image. A bitlist of a selection of the following:
- wxIMAGELIST_DRAW_NORMAL: Draw the image normally.
- wxIMAGELIST_DRAW_TRANSPARENT: Draw the image with transparency.
- wxIMAGELIST_DRAW_SELECTED: Draw the image in selected state.
- wxIMAGELIST_DRAW_FOCUSED: Draw the image in a focused state.
@param solidBackground
For optimisation - drawing can be faster if the function is told
that the background is solid.
*/
virtual bool Draw(int index, wxDC& dc, int x, int y,
int flags = wxIMAGELIST_DRAW_NORMAL,
bool solidBackground = false);
/**
Returns the bitmap corresponding to the given index.
*/
wxBitmap GetBitmap(int index) const;
/**
Returns the icon corresponding to the given index.
*/
wxIcon GetIcon(int index) const;
/**
Returns the number of images in the list.
*/
virtual int GetImageCount() const;
/**
Retrieves the size of the images in the list. Currently, the @a index
parameter is ignored as all images in the list have the same size.
@param index
currently unused, should be 0
@param width
receives the width of the images in the list
@param height
receives the height of the images in the list
@return @true if the function succeeded, @false if it failed
(for example, if the image list was not yet initialized).
*/
virtual bool GetSize(int index, int& width, int& height) const;
/**
Retrieves the size of the image list as passed to Create().
@return the size of the image list, which may be zero if the image list
was not yet initialised.
*/
virtual wxSize GetSize() const;
/**
Removes the image at the given position.
*/
bool Remove(int index);
/**
Removes all the images in the list.
*/
bool RemoveAll();
/**
Replaces the existing image with the new image.
@param index
The index of the bitmap to be replaced.
@param bitmap
Bitmap representing the opaque areas of the image.
@param mask
Monochrome mask bitmap, representing the transparent areas of the image.
@return @true if the replacement was successful, @false otherwise.
@remarks The original bitmap or icon is not affected by the Replace()
operation, and can be deleted afterwards.
*/
bool Replace(int index, const wxBitmap& bitmap,
const wxBitmap& mask = wxNullBitmap);
/**
Replaces the existing image with the new image.
@param index
The index of the bitmap to be replaced.
@param icon
Icon to use as the image.
@return @true if the replacement was successful, @false otherwise.
@remarks The original bitmap or icon is not affected by the Replace()
operation, and can be deleted afterwards.
@onlyfor{wxmsw,wxosx}
*/
bool Replace(int index, const wxIcon& icon);
};