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Whatever the way you get you offset, to access the correct member of the structure you should do:
void *pvIntrinsic pointer to your data
pvFieldPtr = ((char *) pvIntrinsic) + uOffset
Then do the correct cast on it
eg: for a double value
*(double *) pvFieldPtr = doubleValue;
Papa
while (TRUE)
Papa.WillLove ( Bebe ) ;
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Thanks that was what I was looking for.
Just one final question regarding casting. Are they any way I can do a more generalised cast or must it be to the correct type.
Thanks again,
Sweep
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It should be the correct cast, because the size written or read from memory is affected.
A way to solve the issue, let another member in your struct hold the type, and based on it you'll do your cast (enum like member: TYPE_INT, TYPE_FLOAT, TYPE_ ...)
Papa
while (TRUE)
Papa.WillLove ( Bebe ) ;
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Declare a pointer to a SFOO :
struct SFOO *psfoo;
Set the pointer to the address you want :
psfoo = (struct SFOO *)( (char *)BasePointer + offset );
Then you can use standard pointer references :
<br />
psfoo->x = 42;<br />
psfoo->y = 3.141596;<br />
__________________________________________
a two cent stamp short of going postal.
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hi all.. how to display tiff and jpg images on my dialog-based application?
I search for it and they seems too complicated to understand.
I have list of file names want to display one at the time on the dialog when the user click on next or previous button. But I have no experience and no idea of displaying image on the dialog.
Can anyone please tell me how to display tiff and jpg images on dialog Please..
Thanks
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I'm trying to create a filter dropdown similar to Excel AutoFilter feature in a report style CListView. Basically, what I want is a list to pop up when the user clicks on the column heading. When they select an item in the list, the list control redraws itself to include only rows containing the selected value. Any ideas on how to proceed?
Thanks,
Andrew Westberg
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how about making a _PopUp_ menu? You will have to add the CMenu object to your code then #define the ID's for each menu item. Then in your form's OnCommand() function do a switch() statement to see if it's one of the ID's you specified for one of your menu items and take the appropriate action. If this still doesn't help, let me know and I'll try to dig up some code.
[insert witty comment here]
bdiamond 
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Sounds like a good idea. I'll use the LVN_COLUMNCLICK event to add items and track my popup menu. Thanks for the idea.
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Would anyone provide sample source code on this topic?
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How exactly do I get it to draw gray icons? I'm trying to draw icons the way toolbars draw disabled icons (see IE6 toolbar). What part/state am I supposed to call it with?
I've tried pretty much everything, and it still draws a non-gray icon. 
--
...Coca Cola, sometimes war...
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See DrawState and specify DSS_DISABLED.
- Jeremy
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Ah yes, but it doesn't quite do it. Themed toolbars are grayed as in black and white when disabled. DSS_DISABLED embosses the image, which isn't quite what I want.
I will take a look at CxImage here on CP tomorrow. I think it has what I need. 
--
...Coca Cola, sometimes war...
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Check out DitherBlt from WTL then. It's in atlgdi.h.
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Been there, done that. 
If you take a look at the toolbar (coolbar/rebar or whatever microsoft calls it) in IE, you'll see what I mean. The icons are just desaturated. No 3D effects are applied at all. I don't think a simple blit will do the trick for me, unless you or someone knows a clever way to do it with XOR/AND/OR bitblt magic.
--
...Coca Cola, sometimes war...
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Ok now I get it. IE does that by using grayscale bitmaps for the default image-list of the toobar and color ones for the hot-image-list. You set them using TB_SETIMAGELIST and TB_SETHOTIMAGELIST messages. I forget which DLL they're in, maybe comctl32, but if you look you'll find a set of bitmaps for each size, color and grayscale.
WinXP does mentions support for drawing icons in grayscale, but AFAK it's not supported. Other than that, GDI+ maybe?
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JBoschen wrote:
WinXP does mentions support for drawing icons in grayscale, but AFAK it's not supported. Other than that, GDI+ maybe?
I found traces of such support in tmscheme.h (or was it tmschema.h?). I found a property called ...SATURATION..., which was documented with a comment mentioning icons. I did not find any corresponding parts/states though for actually drawing the bitmap. The function DrawThemeIcon(), just draws the image as if I had used ImageList_Draw[ex]().
I did find a function in an article/project written by PJ Arends here on CP which has a function to grayscale bitmaps. I guess I could have a look at it tomorrow.
It's a damn shame I'm so clueless when it comes to image/color theory and advanced GDI. I guess I'll have to order a Petzold book.
--
...Coca Cola, sometimes war...
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There are two formulas i've seen for calculating a grey value from an RGB :
1. byte grey = (R * 0.299) + (G * 0.587) + (B * 0.114);
2. byte grey = (R * 0.2126) + (G * 0.7152) + (B * 0.0722);
The first is what you will generally find documented. It is based on National Television Standard Committee (NTSC) findings from the 50's. It is based on how the human eye perceives light and tuned to how the color TV phosphour (50's) displays RGB colours.
Other sources say these values are no longer representative of current TV/monitor displays and state that the values in 2. should be used.
Regardless, for each pixel :
byte grey = <1 or 2>;
R = grey;
G = grey;
B = grey;
As you've found there are articles here on how to access/change the pixel values in a bitmap.
...cmk
Save the whales - collect the whole set
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Thanks for the 2 formulas, highly appreciated! I will test them both. Just for fun
cmk wrote:
As you've found there are articles here on how to access/change the pixel values in a bitmap.
I did find a function on the net earlier today which transforms an icon into a gray scale icon. I used the function and instered the gray scale icon into an image list. Unfortunately, the image list just wouldn't accept the icon's mask! I used PJ Arend's excellent icon/bitmap/dc debugger, and found that the icon renders perfectly when using DrawIcon. Unfortunately, when using the image list (which I added using ImageList_AddIcon), the mask wasn't used, which resulted in blackness instead of transparency. I used ILD_TRANSPARENT when I drew the icon - which works perfectly for "unmodified" icons. The function which transformed the icon into a grayscale icon looked correct: it saved the mask, and modified each pixel using a formula similar to what you describe above. Then recreated the icon using the image bitmap and saved mask. 
--
...Coca Cola, sometimes war...
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Yes, i spent the last couple days fighting with the imagelist functions as well. I was modifying my toolbar code to accept a normal colour bitmap, apply appropriate filters, generate hot and disabled bitmaps and then generate/apply toolbar imagelists from each of the three bitmaps.
Originally i was using GDI+ Bitmap to manipulate the image (no problem) and then Bitmap::GetHBITMAP() to get a HBITMAP to pass to Imagelist_AddMasked() - no joy. The image would add but no mask would be created. No matter what i did the mask would not generate correctly.
The docs say Imagelist_AddMasked() will only work on 8bbp or less. Even when i created my own mask i couldn't get Imagelist_Add() to work. I even looked at the WINE implimentation.
I ended up writing my own code to access/manipulate the raw bitmap (24/32bbp) and pass that HBITMAP to Imagelist_AddMasked() which works. That's where i stopped. I didn't try Imagelist_AddIcon().
I found this to be infuriating !
Sorry.
...cmk
Save the whales - collect the whole set
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In case you ever need to draw desaturated image list images, here's a piece of code I found in WTL/atlctrlw.h:
void DrawBitmapDisabled(CDCHandle& dc, int nImage, POINT point,
HBRUSH hBrushBackground = ::GetSysColorBrush(COLOR_3DFACE),
HBRUSH hBrush3DEffect = ::GetSysColorBrush(COLOR_3DHILIGHT),
HBRUSH hBrushDisabledImage = ::GetSysColorBrush(COLOR_3DSHADOW))
{
#if (_WIN32_WINNT >= 0x0501) && (_WIN32_IE >= 0x0501)
if(m_bAlphaImages)
{
IMAGELISTDRAWPARAMS ildp = { 0 };
ildp.cbSize = sizeof(IMAGELISTDRAWPARAMS);
ildp.himl = m_hImageList;
ildp.i = nImage;
ildp.hdcDst = dc;
ildp.x = point.x;
ildp.y = point.y;
ildp.cx = 0;
ildp.cy = 0;
ildp.xBitmap = 0;
ildp.yBitmap = 0;
ildp.fStyle = ILD_TRANSPARENT;
ildp.fState = ILS_SATURATE;
ildp.Frame = (DWORD)-100;
::ImageList_DrawIndirect(&ildp);
}
[snip]It doesn't work on Win2k, but then again, old style graying looks ok anyway in that chunky old GUI. 
--
...Coca Cola, sometimes war...
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About icons manipulation, there's an interesting sample in MSDN: IconPro: Icon Manager Sample[^]
And yes, the easiest way to draw icons is IMHO using an ImageList, which accepts HICON entries. Working with a mask should probably help you to do what you want.
Собой остаться дольше...
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I've made a CEdit-derived class called CLockEdit and added a Get- and SetEnabled() function that holds the member variable to see if it should process WM_CHAR messages or not(just so the controls don't look grayed-out when disabled). So I put a CLockEdit control on a dialog that only has that control and the ok and cancel buttons. I allow the user to resize the dialog, and in turn the edit box should also resize. But any CWnd-inherited function like MoveWindow() or GetWindowRect() crashes in wincore.cpp because the hWnd of the control is null. The Methods work like they're supposed to, but I can't resize the window because it crashes on ::IsWindow() in the wincore.cpp file. Any suggestions?
[insert witty comment here]
bdiamond 
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Perhaps is your object instantiated but then not created? Do you use CWnd::SubclassDlgItem in your dialog's OnInitDialog?
Собой остаться дольше...
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No, I'm not really familiar with SubclassDlgItem. I placed an edit box on the dialog, and associated a CEdit variable with it. Then I went and changed the type to CLockEdit instead of CEdit. The other functions I made for the derived class work, but not anything that needs an hWnd. I've read what you said and looked it up, but I can't seem to get this to work. Can you elaborate further?
[insert witty comment here]
bdiamond
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