tkImage

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tkImage

Loads an image file once and draws it in any tkControls window.

tkImageFile holds one decoded image. You declare it, load it once, keep it as long as something shows it, and draw it with tkImage_Paint from a paint callback. The decoded pixels stay in memory; a texture is made the first time the image is drawn in a window and kept for that window, so the same image can appear in the main window, a popup menu and a tooltip. When a window goes, its textures go with it.

Formats are SDL_image's: .png, .bmp, .jpg / .jpeg, .gif, .ico / .cur, .tga, .qoi and more. Controls with an image slot load one for you from a path, for example tkToolbar_SetItemImage and tkIconPanel_SetImage.

Importing

#import "vendor/tkControls/tkImage"

using tkImage
using tkHost
using tkPaint

tkImage re-exports tkHost, and through it tkPaint, which holds TK_IMGFIT_*.

Example

#import "vendor/tkControls/tkApp"
#import "vendor/tkControls/tkImage"
using tkApp
using tkHost
using tkPaint
using tkImage

dim shared as tkImageFile gLogo

sub Main_Paint( byval f as TK_FORM ptr, byval b as TK_PAINT ptr )
    dim as TKRECT rc
    tkRect_Set( rc, 0, 0, tkForm_Scale( f, 96 ), tkForm_Scale( f, 96 ) )
    tkImage_Paint( b, @gLogo, @rc, TK_IMGFIT_ASPECT )   ' nothing when the load failed
end sub

tkApp_Init()
if gLogo.Load( "logo.png" ) = 0 then print "logo.png: " & *SDL_GetError()
dim as TK_FORM ptr f = tkApp_NewForm( "Logo", 320, 200 )
tkForm_OnPaint( f, @Main_Paint )
end tkApp_Run( f )

• Load( path ), LoadFromSurface( s ) (copies an SDL_Surface; you keep yours) and LoadFromPixels( w, h, argb ) (rows of &hAARRGGBB) return non-zero on success. A failed load clears the image held before.
• NaturalWidth / NaturalHeight give the size in pixels; IsValid says whether an image is held; Dispose frees it early.
• TK_IMGFIT_ASPECT fits the image inside the rect with its proportions kept, _STRETCH fills the rect, _CENTER draws it at its natural size, centred and clipped.
• Surface() and Texture( renderer ) hand out what the object owns: never destroy them.

Coming from PsImage

PsImage	tkImage
PsImageFile	tkImageFile
PS_IMGFIT_*	TK_IMGFIT_* (in tkPaint)
buffer.PaintImage( img.Image( ), rc, fit )	tkImage_Paint( b, @img, @rc, fit )
Image( )	Surface( ), Texture( renderer )
LoadFromBitmap (HBITMAP), LoadFromIcon (HICON)	LoadFromSurface, LoadFromPixels

• Decoding is SDL_image's, so the formats are SDL_image's rather than GDI+'s.
• One object draws in every window; there is nothing to reload per window or per scale.

The PsImage page remains the behaviour reference for everything not listed here.

Public declarations

Every public name the module declares, as the source declares it. Signatures are exact; type bodies keep their field comments and drop the rest.

Types

type TKIMG_TEX
    r   as SDL_Renderer ptr
    tex as SDL_Texture ptr
end type

type tkImageFile
    pSurf      as SDL_Surface ptr
    cache(0 to 7) as TKIMG_TEX
    pNextLive  as tkImageFile ptr
    pPrevLive  as tkImageFile ptr
    declare sub DropTextures()
    declare constructor()
    declare destructor()
    declare function Load( byval path as ustring ) as long
    declare function LoadFromSurface( byval s as SDL_Surface ptr ) as long
    declare function LoadFromPixels( byval w as long, byval h as long, byval argb as ulong ptr ) as long
    declare sub Dispose()
    declare function IsValid() as long
    declare function NaturalWidth() as long
    declare function NaturalHeight() as long
    declare function Surface() as SDL_Surface ptr
    declare function Texture( byval r as SDL_Renderer ptr ) as SDL_Texture ptr
    declare sub PurgeRenderer( byval r as SDL_Renderer ptr )
end type

Procedures

sub tkImage_Paint( byval p as TK_PAINT ptr, byval img as tkImageFile ptr, byval rc as TKRECT ptr, byval nFit as long = TK_IMGFIT_ASPECT )

See also

• tkControls
• tkApp, tkHost
• PsImage, the PsControls module