The function HasAlpha doesn't work anymore. It returns .T. even if the image doesn't have an alpha channel. I noticed that the function has been changed in dibbmp.c, don't know exactly when.
EMG
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Board index Bugs report & fixes / Informe de errores y arreglos Bug in HasAlpha()
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This is a sample:
Any ideas?
EMG
#include "Fivewin.ch"
FUNCTION MAIN()
LOCAL hBmp := LOADIMG( "c:\fwh\bitmaps\olga1.jpg" )
? hBmp
? HASALPHA( hBmp )
RETURN NIL
FUNCTION LOADIMG( cFile )
IF !FILE( cFile )
RETURN 0
ENDIF
IF UPPER( CFILEEXT( cFile ) ) = "BMP"
RETURN READBITMAP( 0, cFile )
ENDIF
RETURN GDIP_IMAGEFROMFILE( cFile, .T., UPPER( CFILEEXT( cFile ) ) = "GIF" )Any ideas?
EMG
Try with
#include "Fivewin.ch"
FUNCTION MAIN()
local cFile := "d:\fwh\fwhteam\bitmaps\olga1.jpg"
local hBmp := LoadImg( cFile )
? hBmp, HASALPHA( hBmp )
? GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ), ;
( GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ) = 0 )
cFile := "D:\Fwh\FwhTeam\bitmaps\AlphaBmp\android.bmp"
hBmp := LoadImg( cFile )
? hBmp, HASALPHA( hBmp )
? GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ), ;
( GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ) = 0 )
Return NIL
//----------------------------------------------------------------------------//
FUNCTION LoadImg( cFile )
IF !FILE( cFile )
RETURN 0
ENDIF
IF UPPER( CFILEEXT( cFile ) ) = "BMP"
RETURN READBITMAP( 0, cFile )
ENDIF
Return GDIP_IMAGEFROMFILE( cFile, .T., UPPER( CFILEEXT( cFile ) ) = "GIF" )Cristobal Navarro
Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo
El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces
Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo
El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces
Another possibility
#include "Fivewin.ch"
FUNCTION MAIN()
local oBmp
local cFile := "d:\fwh\fwhteam\bitmaps\olga1.jpg"
local hBmp := LoadImg( cFile )
? hBmp, HASALPHA( hBmp )
? GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ), ;
( GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ) = 0 )
cFile := "D:\Fwh\FwhTeam\bitmaps\AlphaBmp\android.bmp"
hBmp := LoadImg( cFile )
? hBmp, HASALPHA( hBmp )
? GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ), ;
( GdiplusImagePixGetAlpha( GdiPlusImageLoadCachedFile( cFile ) ) = 0 )
cFile := "d:\fwh\fwhteam\bitmaps\olga1.jpg"
oBmp := GdiBmp():New( cFile )
? oBmp:IsAlphaChannel(), oBmp:Is32Bits()
oBmp:Destroy()
cFile := "D:\Fwh\FwhTeam\bitmaps\AlphaBmp\android.bmp"
oBmp := GdiBmp():New( cFile )
? oBmp:IsAlphaChannel(), oBmp:Is32Bits()
oBmp:Destroy()
Return NIL
//----------------------------------------------------------------------------//
FUNCTION LoadImg( cFile )
IF !FILE( cFile )
RETURN 0
ENDIF
IF UPPER( CFILEEXT( cFile ) ) = "BMP"
RETURN READBITMAP( 0, cFile )
ENDIF
Return GDIP_IMAGEFROMFILE( cFile, .T., UPPER( CFILEEXT( cFile ) ) = "GIF" )Cristobal Navarro
Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo
El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces
Hay dos tipos de personas: las que te hacen perder el tiempo y las que te hacen perder la noción del tiempo
El secreto de la felicidad no está en hacer lo que te gusta, sino en que te guste lo que haces
What is the official way to load an image and to check for alpha channel without using classes?
EMG
This is an interesting reading and this code may be the simplest way to do it:
https://www.gamedev.net/topic/607214-get-alpha-channel-from-32bit-bmp/
https://www.gamedev.net/topic/607214-get-alpha-channel-from-32bit-bmp/
struct ABGRStruct {
BYTE a,b,g,r;
};
FILE *f = fopen("the_file_name.bmp", "rb");
if(f){
int w, h;
fseek(f, 0x12, SEEK_SET);
fread(&w, 1, sizeof(int), f);
fread(&h, 1, sizeof(int), f);
fseek(f, 54, SEEK_SET);
int NumPixels = w * h;
for(int i = 0; i < NumPixels; i++){
ABGRStruct Pixel;
fread(&Pixel, 1, 4, f);
// do something with alpha
}
fclose(f);
}Thank you. I will wait for something faster. I'm going to drop alpha channel support in my application, for the moment.
EMG
BitBlt() is the fastest way to manage bitmaps
Not sure if there is a flag we could used for Alpha channel detection
Enrico,
Windows function AlphaBlend() returns a logical value once it tries to paint a bitmap that have transparent or semitransparent pixels:
https://msdn.microsoft.com/en-us/library/windows/desktop/dd183351(v=vs.85).aspx
Thus, we could modify FWH function ABPaint() to return the return value of the AlphaBlend() call there
Windows function AlphaBlend() returns a logical value once it tries to paint a bitmap that have transparent or semitransparent pixels:
https://msdn.microsoft.com/en-us/library/windows/desktop/dd183351(v=vs.85).aspx
Thus, we could modify FWH function ABPaint() to return the return value of the AlphaBlend() call there
Ok, let's try it.
EMG
Please try it using this function:
You have to provide it a hDC and later on call DeleteDC()
You have to provide it a hDC and later on call DeleteDC()
HB_FUNC( ABPAINT )
{
#ifdef _WIN64
HDC hDC = ( HDC ) hb_parnll( 1 );
#else
HDC hDC = ( HDC ) hb_parnl( 1 );
#endif
HDC hDCComp = CreateCompatibleDC( hDC );
BITMAP bm;
HGDIOBJ hOldBmp = SelectObject( hDCComp, ( HBITMAP ) fw_parH( 4 ) );
BLENDFUNCTION blend;
int wDest, hDest;
blend.BlendOp = AC_SRC_OVER;
blend.BlendFlags = 0;
blend.SourceConstantAlpha = IF( hb_parnl( 5 ) != 0, hb_parnl( 5 ), 220 );
blend.AlphaFormat = AC_SRC_ALPHA;
#ifdef _WIN64
GetObject( ( HBITMAP ) hb_parnll( 4 ), sizeof( BITMAP ), ( LPSTR ) &bm );
#else
GetObject( ( HBITMAP ) hb_parnl( 4 ), sizeof( BITMAP ), ( LPSTR ) &bm );
#endif
wDest = bm.bmWidth;
hDest = bm.bmHeight;
if( hb_pcount() > 5 )
{
wDest = hb_parni( 6 );
hDest = hb_parni( 7 );
}
hb_retl( AlphaBlend( hDC, hb_parnl( 2 ), hb_parnl( 3 ), wDest, hDest, hDCComp,
0, 0, bm.bmWidth, bm.bmHeight, blend ) );
SelectObject( hDCComp, hOldBmp );
DeleteDC( hDCComp );
}I don't understand. I have to select the correct painting function to use after checking for alpha channel. Ie:
IF HASALPHA()
use ABPAINT()
ELSE
use something else
ENDIF
EMG
The idea is:
lHasAlpha = ABPaint( hDC, nX, nY, hBitmap, nAlphaLevel )
Yes, but then the image is already printed with the right or wrong function. We need of a checking function that doesn't print the image, I think.
EMG
Page: 1 2 (22 posts)