BITMAP and blitting operations

Functions
MG_EXPORT BOOL GUIAPI	GetBitmapFromDC (HDC hdc, int x, int y, int w, int h, BITMAP *bmp)
	Gets image box on a DC and saves it into a BITMAP object. More...
MG_EXPORT BOOL GUIAPI	FillBoxWithBitmap (HDC hdc, int x, int y, int w, int h, const BITMAP *bmp)
	Fills a box with a BITMAP object. More...
MG_EXPORT BOOL GUIAPI	FillBoxWithBitmapPart (HDC hdc, int x, int y, int w, int h, int bw, int bh, const BITMAP *bmp, int xo, int yo)
	Fills a box with a part of a bitmap oject. More...
MG_EXPORT BOOL GUIAPI	FillBitmapPartInBox (HDC hdc, int box_x, int box_y, int box_w, int box_h, const BITMAP *pbmp, int bmp_x, int bmp_y, int bmp_w, int bmp_h)
	Fills a part of bitmap into a box, and the parts bitmap will be scaled if needed. More...
MG_EXPORT void GUIAPI	BitBlt (HDC hsdc, int sx, int sy, int sw, int sh, HDC hddc, int dx, int dy, DWORD dwRop)
	Performs a bit-block transfer from a device context into another device context. More...
MG_EXPORT void GUIAPI	StretchBlt (HDC hsdc, int sx, int sy, int sw, int sh, HDC hddc, int dx, int dy, int dw, int dh, DWORD dwRop)
	Copies a bitmap from a source rectangle into a destination rectangle, streches the bitmap if necessary. More...
MG_EXPORT BOOL GUIAPI	ScaleBitmapEx (BITMAP *dst, const BITMAP *src, HDC ref_dc)
	Scales a BITMAP object into another BITMAP object by specify algorithm. More...
MG_EXPORT gal_pixel GUIAPI	GetPixelInBitmapEx (const BITMAP *bmp, int x, int y, Uint8 *alpha)
	Returns the pixel value in a BITMAP object. More...
static gal_pixel GUIAPI	GetPixelInBitmap (const BITMAP *bmp, int x, int y)
	Returns the pixel value in a BITMAP object. More...
static BOOL GUIAPI	SetPixelInBitmap (const BITMAP *bmp, int x, int y, gal_pixel pixel)
	Sets pixel value in a BITMAP object. More...
MG_EXPORT BOOL GUIAPI	SaveScreenRectContent (const RECT *rcWin, const char *filename)
	Saves content of a rectangle in the screen to a file. More...
MG_EXPORT BOOL GUIAPI	SaveMainWindowContent (HWND hWnd, const char *filename)
	Saves content of a main window to a file. More...

Detailed Description

Example:

{
    int tox = 800, toy = 800;
    int count;
    BITMAP bitmap;
    unsigned int start_tick, end_tick;

    /* Load the bitmap from the file. */
    if (LoadBitmap (hdc, &bitmap, "res/icon.bmp"))
        return;

    bitmap.bmType = BMP_TYPE_ALPHACHANNEL;

    /* Fill a box with the bitmap with alpha channel. */
    start_tick = GetTickCount ();
    count = 1000;
    while (count--) {
        tox = rand() % 800;
        toy = rand() % 800;

        /* Set a random alpha channel. */
        bitmap.bmAlpha = rand() % 256;
        /* Fill the box. */
        FillBoxWithBitmap (hdc, tox, toy, 0, 0, &bitmap);
    }
    end_tick = GetTickCount ();
    TellSpeed (hwnd, start_tick, end_tick, "Alpha Blended Bitmap", 1000);

    bitmap.bmType = BMP_TYPE_ALPHACHANNEL | BMP_TYPE_COLORKEY;
    /* Set the color key (the transparent pixel) of the bitmap. */
    bitmap.bmColorKey = GetPixelInBitmap (&bitmap, 0, 0);

    /* Fill a box with the bitmap with alpha channel and color key. */
    start_tick = GetTickCount ();
    count = 1000;
    while (count--) {
        tox = rand() % 800;
        toy = rand() % 800;

        /* Set a random alpha channel. */
        bitmap.bmAlpha = rand() % 256;
        /* Fill the box. */
        FillBoxWithBitmap (hdc, tox, toy, 0, 0, &bitmap);
    }
    end_tick = GetTickCount ();
    TellSpeed (hwnd, start_tick, end_tick, "Alpha Blended Transparent Bitmap", 1000);

    UnloadBitmap (&bitmap);
}

{
    /* Create a memory DC which hanve alpha per-pixel. */
    mem_dc = CreateMemDC (400, 100, 16, MEMDC_FLAG_HWSURFACE | MEMDC_FLAG_SRCALPHA,
                    0x0000F000, 0x00000F00, 0x000000F0, 0x0000000F);

    /* Set brush color and fill a box. */
    SetBrushColor (mem_dc, RGBA2Pixel (mem_dc, 0xFF, 0xFF, 0x00, 0xFF));
    FillBox (mem_dc, 0, 0, 200, 50);

    /* Set another brush color and fill a box */
    SetBrushColor (mem_dc, RGBA2Pixel (mem_dc, 0xFF, 0xFF, 0x00, 0x40));
    FillBox (mem_dc, 200, 0, 200, 50);

    /* Set another brush color and fill a box */
    SetBrushColor (mem_dc, RGBA2Pixel (mem_dc, 0xFF, 0xFF, 0x00, 0x80));
    FillBox (mem_dc, 0, 50, 200, 50);

    /* Set another brush color and fill a box */
    SetBrushColor (mem_dc, RGBA2Pixel (mem_dc, 0xFF, 0xFF, 0x00, 0xC0));
    FillBox (mem_dc, 200, 50, 200, 50);
    SetBkMode (mem_dc, BM_TRANSPARENT);

    /* Set a text color and output the text */
    SetTextColor (mem_dc, RGBA2Pixel (mem_dc, 0x00, 0x00, 0x00, 0x80));
    TabbedTextOut (mem_dc, 0, 0, "Memory DC with alpha.\n"
                                 "The source DC have alpha per-pixel.");

    /* Blitting to a client DC. */
    start_tick = GetTickCount ();
    count = 100;
    while (count--) {
        BitBlt (mem_dc, 0, 0, 400, 100, hdc, rand () % 800, rand () % 800);
    }
    end_tick = GetTickCount ();
    TellSpeed (hwnd, start_tick, end_tick, "Alpha Blit", 100);

    /* delete the momory DC. */
    DeleteMemDC (mem_dc);
}

Function Documentation

void GUIAPI BitBlt	(	HDC	hsdc,
		int	sx,
		int	sy,
		int	sw,
		int	sh,
		HDC	hddc,
		int	dx,
		int	dy,
		DWORD	dwRop
	)

Performs a bit-block transfer from a device context into another device context.

This function performs a bit-block transfer of the color data cooresponding to a rectangle of pixels from the specified source device context hsdc into a destination device context hddc. (sx,sy,sw,sh) specifies the rectangle in the source DC, and (dx,dy) specifies the position of the rectangle in the destination DC. Note that the size of the two rectangles are identical.

Note that all coordinates should be in the device space.

Parameters

hsdc	The source device context.
sx	The x coordinate of the upper-left corner of the rectangle in the source DC.
sy	The y coordinate of the upper-left corner of the rectangle in the source DC.
sw	The width of the source rectangle.
sh	The height of the source rectangle.
hddc	The destination device context hddc.
dx	The x coordinate of the upper-left corner of the rectangle in the destination DC.
dy	The y coordinate of the upper-left corner of the rectangle in the destination DC.
dwRop	The raster operation, currently ignored.

Note

The alpha and color key settings of the source DC will come into play.

See also

StretchBlt, SetMemDCAlpha, SetMemDCColorKey

BOOL FillBitmapPartInBox	(	HDC	hdc,
		int	box_x,
		int	box_y,
		int	box_w,
		int	box_h,
		const BITMAP *	pbmp,
		int	bmp_x,
		int	bmp_y,
		int	bmp_w,
		int	bmp_h
	)

Fills a part of bitmap into a box, and the parts bitmap will be scaled if needed.

This function gives an intuitionistic way to use function FillBoxWidthBitmapPart.

Parameters

hdc	The target DC to show bitmap
box_x	The left of target box
box_y	The top of target box
box_w	The width of target box
box_h	The height of target box
pbmp	The bitmap which will be showed in the hdc
bmp_x	The visible part's left of bitmap
bmp_y	The visible part's top of bitmap
bmp_w	The visible part's width of bitmap
bmp_h	The visible part's height of bitmap

See also

FillBoxWidthBitmapPart

BOOL GUIAPI FillBoxWithBitmap	(	HDC	hdc,
		int	x,
		int	y,
		int	w,
		int	h,
		const BITMAP *	bmp
	)

Fills a box with a BITMAP object.

This function fills a box with a BITMAP object pointed to by bmp. (x,y) is the upper-left corner of the box, and w, h are the width and the height of the box respectively.

This function will scale the bitmap when necessary; that is, when the width or the height of the box is not equal to the with or the height of the BITMAP object.

Parameters

hdc	The device context.
x	The x coordinate of the upper-left corner of the box.
y	The y coordinate of the upper-left corner of the box.
w	The width of the box. Can be zero, means the width or the height will be equal to the width or the height of the BITMAP object.
h	The height of the box. Can be zero, means the width or the height will be equal to the width or the height of the BITMAP object.
bmp	The pointer to the BITMAP object.

Returns

TRUE on success, otherwise FALSE.

Note

You can specify the alpha value or the color key of the BITMAP object, and the current raster operation was set by SetRasterOperation for the DC will override the alpha value of color key if ROP is not ROP_SET.

If the bitmap has BMP_TYPE_RLE, the target w and h will be ignored. That is, the scale of the bitmap is not supported for RLE encoded bitmap.

See also

FillBoxWithBitmapPart, GetBitmapFromDC, Bitmap file load/save operations

BOOL GUIAPI FillBoxWithBitmapPart	(	HDC	hdc,
		int	x,
		int	y,
		int	w,
		int	h,
		int	bw,
		int	bh,
		const BITMAP *	bmp,
		int	xo,
		int	yo
	)

Fills a box with a part of a bitmap oject.

This function fills a box with a part of a bitmap object pointed to by bmp. (x,y) is the upper-left corner of the box, and w, h are the width and the height of the box respectively. (xo, yo) is the start position of the part box in the bitmap relative to upper-left corner of the bitmap, and bw, bh are the width and the height of the full bitmap expected.

If bw or bh is less than or equal to zero, this function will use the original width and height of the bitmap, else it will scale the BITMAP object when necessary; that is, when bw or bh is not equal to the width or the height of the BITMAP object.

Parameters

hdc	The device context.
x	The x coordinate of the upper-left corner of the box.
y	The y coordinate of the upper-left corner of the box.
w	The width of the box.
h	The height of the box.
bw	The width of the full bitmap expected. Can be zero, means the width or the height will be equal to the width or the height of the BITMAP object.
bh	The height of the full bitmap expected. Can be zero, means the width or the height will be equal to the width or the height of the BITMAP object.
xo	xo,yo: The start position of the part box in the bitmap relative to upper-left corner of the BITMAP object.
yo	xo,yo: The start position of the part box in the bitmap relative to upper-left corner of the BITMAP object.
bmp	The pointer to the BITMAP object.

Returns

TRUE on success, otherwise FALSE.

Note

1: You can specify the alpha value or the color key of the BITMAP object, and the current raster operation was set by SetRasterOperation for the DC will override the alpha value or the color key if ROP is not ROP_SET.

2: xo/yo must be greater zero and (xo + w) < bw, (yo + h) < bh. else with fill nothing.

3: xo/yo must be multiply scale factor when bitmap scaled.

4: if bw or bh is not equal to he width or the height of the BITMAP object, it will be scale bitmap, but fill box is also (0, 0, w,h).

The RLE encoded bitmap is not supported by this function so far.

See also

FillBoxWithBitmap, GetBitmapFromDC, Bitmap structure

BOOL GUIAPI GetBitmapFromDC	(	HDC	hdc,
		int	x,
		int	y,
		int	w,
		int	h,
		BITMAP *	bmp
	)

Gets image box on a DC and saves it into a BITMAP object.

This function gets image box on the specified device context hdc, and saves the image bits into the BITMAP object pointed to by bmp. The image box begins at (x,y), and is w wide and h high. You must make sure that bmp->bits is big enough to store the image.

Parameters

hdc	The device context.
x	The x coordinate in pixels of upper-left corner of the image box.
y	The y coordinate in pixels of upper-left corner of the image box.
w	The width of the image box.
h	The height of the image box.
bmp	The pointer to the BITMAP object.

Note

If BITMAP's bmPitch is zero or bmBits is NULL, it will be malloc bmBits internal, you need init the BITMAP surely(such as InitBitmap) or memset(bmp, 0, sizeof(BITMAP)).

See also

FillBoxWithBitmap, Bitmap structure

static inline gal_pixel GUIAPI GetPixelInBitmap ( const BITMAP *  bmp, int  x, int  y  )

inlinestatic

Returns the pixel value in a BITMAP object.

This function returns the pixel value at the position (x,y) in the BITMAP object bmp.

Parameters

bmp	The BITMAP object.
x	x,y: The position of the pixel in the bitmap relative to the upper-left corner of the bitmap.
y	x,y: The position of the pixel in the bitmap relative to the upper-left corner of the bitmap.

Returns

The pixel value, if the position is out of the bitmap, zero returned.

See also

SetPixelInBitmap, Bitmap structure

Definition at line 4876 of file gdi.h.

References GetPixelInBitmapEx(), and NULL.

gal_pixel GUIAPI GetPixelInBitmapEx	(	const BITMAP *	bmp,
		int	x,
		int	y,
		Uint8 *	alpha
	)

Returns the pixel value in a BITMAP object.

This function returns the pixel value and alpha at the position (x,y) in the BITMAP object bmp.

Parameters

bmp	The BITMAP object.
x	x,y: The position of the pixel in the bitmap relative to the upper-left corner of the bitmap.
y	x,y: The position of the pixel in the bitmap relative to the upper-left corner of the bitmap.
alpha	The point to alpha of position (x, y).

Returns

The pixel value, if the position is out of the bitmap, zero returned.

Note

if the bitmap with BMP_TYPE_ALPHA_MASK flag, the alpha value will be read from bmp->AlphaMask(Bitmap Alpha Mask array).

See also

SetPixelInBitmapEx, Bitmap structure

Referenced by GetPixelInBitmap().

BOOL GUIAPI SaveMainWindowContent	(	HWND	hWnd,
		const char *	filename
	)

Saves content of a main window to a file.

This function saves the content of the main window hWnd to the image file filename. MiniGUI uses the extension name of the file to determine the format of the image file.

Parameters

hWnd	Handle to the main window.
filename	The name of the image file.

Returns

TRUE on success, otherwise FALSE.

Note

Only defined for _MGMISC_SAVESCREEN.

See also

Bitmap file load/save operations

Referenced by SetPixelInBitmap().

BOOL GUIAPI SaveScreenRectContent	(	const RECT *	rc,
		const char *	filename
	)

Saves content of a rectangle in the screen to a file.

This function saves the content of the rect rc to the image file filename. MiniGUI uses the extension name of the file to determine the format of the image file.

Parameters

rc	The RECT object defined the rectangle in the screen.
filename	The name of the image file.

Returns

TRUE on success, otherwise FALSE.

Note

Only defined for _MGMISC_SAVESCREEN.

See also

Bitmap file load/save operations

Referenced by SetPixelInBitmap().

BOOL GUIAPI ScaleBitmapEx	(	BITMAP *	dst,
		const BITMAP *	src,
		HDC	ref_dc
	)

Scales a BITMAP object into another BITMAP object by specify algorithm.

This function scales a BITMAP object src into another BITMAO object dst by specify algorithm. The source rectangle and the destination rectangle both are defined in the BITMAP objects.

Parameters

dst	The destination BITMAP object.
src	The srouce BITMAP object.
ref_dc	The device context of Bitmap's relative device dc.

Returns

TRUE on success, otherwise FALSE.

Note

you should init the dst Bitmap first, such as bmPitch and bmBits.

See also

FillBoxWithBitmap, StretchBlt, Bitmap structure

static inline BOOL GUIAPI SetPixelInBitmap ( const BITMAP *  bmp, int  x, int  y, gal_pixel  pixel  )

inlinestatic

Sets pixel value in a BITMAP object.

This function sets the pixel value at the position (x,y) in the BITMAP object bmp.

Parameters

bmp	The BITMAP object.
x	x,y: The position of the pixel in the bitmap relative to the upper-left corner of the bitmap.
y	x,y: The position of the pixel in the bitmap relative to the upper-left corner of the bitmap.
pixel	The pixel value.

Returns

TRUE on success. If the position is out of the bitmap, FALSE returned.

See also

GetPixelInBitmap, Bitmap structure

Definition at line 4928 of file gdi.h.

References CreateIconEx(), LoadIconFromFile(), LoadIconFromMem(), NULL, SaveMainWindowContent(), and SaveScreenRectContent().

void GUIAPI StretchBlt	(	HDC	hsdc,
		int	sx,
		int	sy,
		int	sw,
		int	sh,
		HDC	hddc,
		int	dx,
		int	dy,
		int	dw,
		int	dh,
		DWORD	dwRop
	)

Copies a bitmap from a source rectangle into a destination rectangle, streches the bitmap if necessary.

This function copies a bitmap from a source rectangle into a destination rectangle, streching or compressing the bitmap to fit the dimension of the destination rectangle, if necessary. This function is similar with

See also

BitBlt function except the former scaling the bitmap. (dw,dh) specifies the size of the destination rectangle.

Parameters

hsdc	The source device context.
sx	The x coordinate of the upper-left corner of the rectangle in the source DC.
sy	The y coordinate of the upper-left corner of the rectangle in the source DC.
sw	The width of the source rectangle.
sh	The height of the source rectangle.
hddc	The destination device context hddc.
dx	The x coordinate of the upper-left corner of the rectangle in the destination DC.
dy	The y coordinate of the upper-left corner of the rectangle in the destination DC.
dw	The width of the destination rectangle.
dh	The height of the destination rectangle.
dwRop	The raster operation, currently ignored.

Note

The source rect should be contained in the device space entirely, and all coordinates should be in the device space.

The source DC and dest DC must compatible, else will do nothing.

The alpha and color key settings of the source DC will not come into play.

See also

BitBlt, SetMemDCAlpha, SetMemDCColorKey