Bos Taurus
Graphic Library for HMG
Version 1.0.6
© Dr. Claudio Soto
Uruguay, December 2012
CONTENT
1)
What is HMG?
2) What
is the graphics library Bos Taurus?
3) Why
use the graphics library Bos Taurus?
4) How
to use the graphics library Bos Taurus?
5)
Prototype Example
A)
HMG Official
B)
HMG Extended
6)
Bos Taurus: Functions Reference Guide
A)
Information about the Library
B)
Information about the Environment
C)
Repaint the Client Area Functions
D)
Bitmap Functions
E) Functions
that Get/Release Handle Device Context
F) Functions
for Drawing on a Device Context
G) Functions
of Connection Between HMG Controls and Bos Taurus.
7) Bos Taurus: List of the Functions
1)
What is HMG?
Harbour-MiniGUI (HMG) is a GUI free
open source library for Windows developed for the Harbour compiler. Harbour is a cross-platform
free open source compiler for
the xBase language (https://harbour.github.io), is 100%
compatible with Clipper language.
There are several teams of developers Harbour-GUI libraries, the two most important free
libraries are HMG Official (www.hmgforum.com) and HMG
Extended (http://hmgextended.com). In
this text we will use the acronym HMG
to generically refer to both versions of HMG (Official and Extended)
interchangeably.
2) What
is the graphics library Bos Taurus?
Bos Taurus is a set of graphics functions (free open code)
written in C and Harbour based in the Windows GDI
functions specially developed for easy programming of the ON PAINT events in HMG.
In the past, the ON PAINT event was little used in
applications developed in HMG due to malfunction of this event, but recently
since version 3.0.43 of HMG Official (2012/08/30)
and version 2.1.5 of HMG Extended (2012/09/12)
the bug was corrected.
The ON PAINT event runs in response to WM_PAINT
message that the Windows System sent to a window for inform that have to paint
the client area. In HMG the ON PAINT event allows paint directly on the client
area of a window before paint the Controls (Button, Grid, Image, ComboBox, etc.) and before paint the Draw Commands (Draw
Graph, Rectangle, Line, etc.).
The BosTaurus_ChangeLog.TXT
contains the latest updates in the source files of the library. From version
1.0.3, Bos Taurus supports the ANSI and UNICODE character set.
3) Why
use the graphics library Bos Taurus?
Because in HMG exist very few native functions to draw
and manipulate graphic images.
In Bos Taurus the
draw functions are called with a Handle
Device Context (hDC) obtained from the selected
output device (desktop, client area, bitmap, etc.) just like when programming
in C for Windows. This allows the use of the same functions of drawing and the
easy transfer of graphics from one device to another irrespective of the output
device selected. For example if a drawing function we pass to a hDC of window, the function draw in the client area of the
window, however, if we pass the hDC associated with a
Bitmap, the function draw in the Bitmap image.
The system of use of hDC in the functions will help
other people to create other drawing functions fully compatible with the
graphics library Bos Taurus, the programmer only have to
use the appropriate hDC that gives the graphics
library Bos Taurus. In fact with this system can
be implemented in Harbour virtually all graphics
functions (GDI) of Windows thereby providing a great power of graphic
manipulation to the programmer.
4) How
to use the graphics library Bos Taurus?
It is very easy to use the graphics library Bos Taurus in HMG because it is part of
the library of HMG Official and HMG Extended.
5)
Prototype Example
This example is very simple. Loads a Bitmap to the
start the application and puts the background image, before drawing the image
paints a vertical colors gradient from white to black. When you close the
application frees of the memory the handle of the Bitmap. For more information see the demos that accompanying the Bos Taurus.
A)
HMG Official
#include "HMG.CH"
FUNCTION MAIN
PRIVATE hBitmap := 0
DEFINE WINDOW Win1;
AT 0,0;
WIDTH 700;
HEIGHT 600;
TITLE "Prototype
Demo";
MAIN;
ON INIT Proc_ON_INIT ();
ON RELEASE Proc_ON_RELEASE ();
ON PAINT Proc_ON_PAINT ()
// Definition of
Application Controls
@ 435, 280 BUTTON
Button1 CAPTION "Click";
ACTION MsgInfo ("Hello")
END WINDOW
CENTER WINDOW Win1
ACTIVATE WINDOW Win1
RETURN
PROCEDURE Proc_ON_INIT
hBitmap := BT_BitmapLoadFile ("HMG.bmp")
RETURN
PROCEDURE Proc_ON_RELEASE
BT_BitmapRelease
(hBitmap)
RETURN
PROCEDURE Proc_ON_PAINT
LOCAL
hDC, BTstruct
hDC := BT_CreateDC
("Win1", BT_HDC_INVALIDCLIENTAREA, @BTstruct)
BT_DrawGradientFillVertical
(hDC,;
0, 0,;
BT_ClientAreaWidth ("Win1"),;
BT_ClientAreaHeight("Win1"),;
WHITE,
BLACK)
BT_DrawBitmap
(hDC, 35, 200, 300, 250, BT_COPY,
hBitmap)
BT_DeleteDC
(BTstruct)
RETURN
B)
HMG Extended
#include "MiniGUI.CH"
#include "BosTaurus.CH"
FUNCTION MAIN
PRIVATE hBitmap := 0
DEFINE WINDOW Win1;
AT 0,0;
WIDTH 700;
HEIGHT 600;
TITLE "Prototype
Demo";
MAIN;
ON INIT Proc_ON_INIT ();
ON RELEASE Proc_ON_RELEASE ();
ON PAINT Proc_ON_PAINT ()
ON SIZE
BT_ClientAreaInvalidateAll ("Win1");
ON MAXIMIZE BT_ClientAreaInvalidateAll ("Win1")
// Definition of
Application Controls
@ 435, 280 BUTTON
Button1 CAPTION "Click";
ACTION MsgInfo ("Hello")
END WINDOW
CENTER WINDOW Win1
ACTIVATE WINDOW Win1
RETURN
PROCEDURE Proc_ON_INIT
hBitmap := BT_BitmapLoadFile ("HMG.bmp")
BT_ClientAreaInvalidateAll
("Win1")
RETURN
PROCEDURE Proc_ON_RELEASE
BT_BitmapRelease
(hBitmap)
RETURN
PROCEDURE Proc_ON_PAINT
LOCAL
hDC, BTstruct
hDC := BT_CreateDC
("Win1", BT_HDC_INVALIDCLIENTAREA, @BTstruct)
0, 0,;
BT_ClientAreaWidth
("Win1"),;
BT_ClientAreaHeight("Win1"),;
WHITE,
BLACK)
BT_DrawBitmap
(hDC, 35, 200, 300, 250, BT_COPY,
hBitmap)
BT_DeleteDC
(BTstruct)
RETURN
6) Bos Taurus: Functions Reference Guide.
A)
Information about the Library
BT_InfoName ()
Return a string with the name of the library: "Bos Taurus"
BT_InfoVersion ()
Return a string with the current version of the
library, for example: "1.0.0"
BT_InfoAuthor ()
Return a string with the name of the author: "©
Dr. Claudio Soto (from Uruguay)"
B)
Information about the Environment
BT_GetDesktopHandle ()
Return a handle to the desktop (hWin).
The desktop window covers the entire screen.
BT_DesktopWidth ()
Return the width of the screen in pixels.
BT_DesktopHeight ()
Return the height of the screen in pixels.
BT_WindowWidth (Win)
Return the width of the specified window in pixels.
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
BT_WindowHeight (Win)
Return the height of the specified window in pixels.
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
BT_ClientAreaWidth (Win)
Return the width of the client area of the specified
window in pixels. The client area includes the area of the Status Bar.
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
BT_ClientAreaHeight (Win)
Return the height of the client area of the specified
window in pixels. The client area includes the area of the Status Bar.
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
BT_StatusBarWidth (cFormName)
Return the width of the Status Bar of the specified
window in pixels. If not defined (not exist) the Status Bar, returns zero.
cFormName: is the name of the window(e.g. "Win1").
BT_StatusBarHeight (cFormName)
Return the height of the Status Bar of the specified
window in pixels. If not defined (not exist) the Status Bar, returns zero.
cFormName: is the name of the window(e.g. "Win1").
C)
Repaint the Client Area Functions
BT_ClientAreaInvalidateAll (Win, lErase)
Force to redraw the all of the client area of the
specified window.
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
lErase: specifies whether the background within the update
region is to be erased when the update region is processed. If this parameter
is TRUE (.T.), the background is erased. If this parameter is FALSE (.F.), the
background remains unchanged. For default: lErase = .F.
BT_ClientAreaInvalidateRect (Win, Row, Col, Width, Height, lErase)
Force to redraw the specified rectangle of the client
area of the specified window.
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
Row, Col, Width, Height: specifies the dimensions in pixels of the rectangle
to redraw. For default: Row = 0, Col = 0, Width = BT_ClientAreaWidth(Win), Height = BT_ClientAreaHeight(Win).
lErase: specifies whether the background within the update
region is to be erased when the update region is processed. If this parameter
is TRUE (.T.), the background is erased. If this parameter is FALSE (.F.), the
background remains unchanged. For default: lErase = .F.
D)
Bitmap Functions
BT_BitmapLoadFile (cFileName)
Loads an image (BMP, JPG, GIF, TIF or PNG) from the
disk or resources and returns a handle to bitmap format image (hBitmap).
cFileName: is the name of the file or of the resource that
contains the image.
BT_BitmapLoadEMF (cFileName, aRGBcolor_Fill_Bk, NewWidht, NewHeight, Mode_Stretch)
Loads an EMF (Enhanced Meta File) image from the disk
or resources and returns a handle to bitmap format image (hBitmap).
cFileName: is the name of the file or of the resource that
contains the image.
aRGBcolor_Fill_Bk: array containing the RGB colors that paint the
background of the bitmap. For default: aRGBcolor_Fill_Bk = {0,0,0} = BLACK.
New_Width, New_Height: is the new size of the bitmap image. For default this
values are the original width and height of the EMF image.
Mode_Stretch: sets the mode as the image of origin is adjusts (is
stretches or compresses) in the new size bitmap, it is one of the constants:
BT_SCALE or BT_STRETCH (defined in BosTaurus.CH). For default Mode_Stretch =
BT_STRETCH.
BT_BitmapSaveFile (hBitmap, cFileName, nTypePicture)
Save an image (BMP, JPG, GIF, TIF or PNG) in the disk.
hBitmap: is a handle to the bitmap image.
cFileName: is the name of the file to save.
nTypePicture: specifies the format in which you want to save the
image, it is one of the constants: BT_FILEFORMAT_BMP, BT_FILEFORMAT_JPG,
BT_FILEFORMAT_GIF, BT_FILEFORMAT_TIF or BT_FILEFORMAT_PNG (defined in
BosTaurus.CH). For default nTypePicture = BT_FILEFORMAT_BMP.
BT_BitmapRelease (hBitmap)
Release a bitmap of the memory.
hBitmap: is a handle to bitmap.
Note: all of the handles of bitmap obtained from load,
create, clone, copy, etc. a bitmap image is responsibility of the application
for his release before close.
BT_BitmapWidth (hBitmap)
Return the width of the specified bitmap in pixels.
hBitmap: is a handle to bitmap.
BT_BitmapHeight (hBitmap)
Return the height of the specified bitmap in pixels.
hBitmap: is a handle to bitmap.
BT_BitmapBitsPerPixel (hBitmap)
Return the bits per pixel of the specified bitmap.
hBitmap: is a handle to bitmap.
BT_BitmapCreateNew (Width, Height, aRGBcolor_Fill_Bk)
Creates a bitmap in the memory and returns a handle to
bitmap (hBitmap).
Width, Height: are the dimensions of the bitmap in pixels.
aRGBcolor_Fill_Bk: array containing the RGB colors that paint the
background of the bitmap. For default: aRGBcolor_Fill_Bk = {0,0,0} = BLACK.
BT_BitmapClone (hBitmap, Row, Col, Width,
Height)
Clones the specified bitmap and returns a handle to
the cloned bitmap.
hBitmap: is a handle to the origin bitmap.
Row, Col, Width, Height: specifies the dimensions in pixels of the rectangle
to clone. For default: Row = 0, Col = 0, Width = BT_BitmapWidth(hBitmap), Height = BT_BitmapHeight(hBitmap).
BT_BitmapCopyAndResize (hBitmap, New_Width, New_Height, Mode_Stretch, Algorithm)
Copy and resizes the specified bitmap and returns a
handle to the bitmap with the new size.
hBitmap: is a handle to the origin bitmap.
New_Width, New_Height: is the new size of the bitmap image.
Mode_Stretch: sets the mode as the bitmap of origin is adjusts (is
stretches or compresses) in the new size bitmap, it is one of the constants:
BT_SCALE or BT_STRETCH (defined in BosTaurus.CH). For default Mode_Stretch =
BT_STRETCH.
Algorithm: sets the mode as the bitmap is resized, it is one of
the constants: BT_RESIZE_COLORONCOLOR, BT_RESIZE_HALFTONE or BT_RESIZE_BILINEAR
(defined in BosTaurus.CH). For default Algorithm
= BT_RESIZE_HALFTONE.
BT_BitmapPaste (hBitmap_D, Row_D, Col_D, Width_D,
Height_D, Mode_Stretch, hBitmap_O)
Paste a bitmap (origin) into another bitmap
(destination).
hBitmap_D: is a handle to the destination bitmap.
Row_D, Col_D, Width_D,
Height_D: specifies the size of the rectangle in pixels in the
destination bitmap where you will paste the origin bitmap. For default: Row_D = 0, Col_D = 0, Width = BT_BitmapWidth(hBitmap_D), Height =
BT_BitmapHeight(hBitmap_D).
Mode_Stretch: sets the mode as the bitmap of origin is adjusts (is
stretches or compresses) in the specified rectangle in the destination bitmap,
it is one of the constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in
BosTaurus.CH).
hBitmap_O: is a handle to the origin bitmap.
BT_BitmapPasteTransparent (hBitmap_D, Row_D, Col_D, Width_D,
Height_D, Mode_Stretch, hBitmap_O, aRGBcolor_transp)
Paste a transparent bitmap (origin) into another
bitmap (destination).
hBitmap_D: is a handle to the destination bitmap.
Row_D, Col_D, Width_D,
Height_D: specifies the size of the rectangle in pixels in the
destination bitmap where you will paste the origin bitmap. For default: Row_D = 0, Col_D = 0, Width = BT_BitmapWidth(hBitmap_D), Height =
BT_BitmapHeight(hBitmap_D).
Mode_Stretch: sets the mode as the bitmap of origin is adjusts (is
stretches or compresses) in the specified rectangle in the destination bitmap,
it is one of the constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in
BosTaurus.CH).
hBitmap_O: is a handle to the origin bitmap.
aRGBcolor_transp: array containing the RGB colors to treat as
transparent in the origin bitmap. For default: aRGBcolor_transp = color of the first pixel of the
origin bitmap.
BT_BitmapPasteAlphaBlend (hBitmap_D, Row_D, Col_D, Width_D,
Height_D, Alpha, Mode_Stretch,
hBitmap_O)
Paste a bitmap (origin) with Alpha Blend effect (that
make the pixels to be transparent or semi transparent)
into another bitmap (destination).
hBitmap_D: is a handle to the destination bitmap.
Row_D, Col_D, Width_D,
Height_D: specifies the size of the rectangle in pixels in the
destination bitmap where you will paste the origin bitmap. For default: Row_D = 0, Col_D = 0, Width = BT_BitmapWidth(hBitmap_D), Height =
BT_BitmapHeight(hBitmap_D).
Alpha: is alpha blending value to be applied to the entire source bitmap (range 0
to 255, transparent = 0, opaque = 255).
Mode_Stretch: sets the mode as the bitmap of origin is adjusts (is
stretches or compresses) in the specified rectangle in the destination bitmap,
it is one of the constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in
BosTaurus.CH).
hBitmap_O: is a handle to the origin bitmap.
BT_BitmapInvert (hBitmap)
Invert the colors of an image (makes a negative of the
original image).
hBitmap: is a handle to bitmap.
BT_BitmapGrayness (hBitmap, Gray_Level)
Set the grayness of the specified bitmap.
hBitmap: is a handle to bitmap.
Gray_Level: is the gray level in percentage (range 0 to 100%,
none = 0, full = 100).
BT_BitmapBrightness (hBitmap, Light_Level)
Change the brightness of the specified bitmap.
hBitmap: is a handle to bitmap.
Light_Level: is the light level (range -255 to +255, black = -255,
white = +255, none = 0).
BT_BitmapContrast (hBitmap, ContrastAngle)
Increase the contrast of the colors in an image.
hBitmap: is a handle to bitmap.
ContrastAngle: is the angle of the slope (in radians) of the
contrast transform.
BT_BitmapModifyColor (hBitmap, RedLevel, GreenLevel, BlueLevel)
Increases or decreases the colors channels of an image.
hBitmap: is a handle to bitmap.
RedLevel: is the Red color level to change (range -255 to
+255, none = 0).
GreenLevel: is the Green color level to change (range -255 to
+255, none = 0).
BlueLevel: is the Blue color level to change (range -255 to
+255, none = 0).
BT_BitmapGammaCorrect (hBitmap, RedGamma, GreenGamma, BlueGamma)
Image displaying suffers from photometric distortions
caused by the nonlinear response of display devices to lightness. The
photometric response of a displaying device is known as the gamma response
characteristic. Display monitors for different operating systems use different
gammas. To compensate for these differences, the gamma of the image needs to be
corrected. A gamma correction with gamma equal to 1.0 is an identity color
transformation. Gamma less than 1.0 makes a picture look darker, and gamma
larger than 1.0 makes a picture look lighter.
hBitmap: is a handle to bitmap.
RedGamma: is the Gamma Red color level to change (normally
range between 0.2 and 5.0, none = 1.0).
GreenGamma: is the Gamma Green color level to change (normally
range between 0.2 and 5.0, none = 1.0).
BlueGamma: is the Gamma Blue color level to change
(normally range between 0.2 and 5.0, none = 1.0).
BT_BitmapConvolutionFilter3x3
(hBitmap,
aFilter)
The convolution is a matrix (or two-dimensional
arrangement) applied to an image. The elements of this array are integers values. The result of this operation is a new
image that has been filtered. The convolution basically modifies the color of a
pixel based on the color
of the neighboring pixels. For each color channel, the color value for each
pixel is calculated on the original color and the color of the surrounding
pixels.
hBitmap: is a handle to bitmap.
aFilter: is an array with the following values:
{ k1, k2, k3,
k4, k5, k6,
k7, k8, k9,
Divisor, Bias }
Where k1 ... k9 are the values of the 3x3 matrix that multiply the pixels. The center
cell value (k5) multiplies the pixel that is currently processing. Divisor determines the
brightness of the final image and Bias
increments (positive value) or decrements (negative value) the end color of the
currently processed pixel. For more details see the demo10.
---------------------------------------------------------
RULES OF
THUMB TO CREATE USER DEFINED FILTERS
---------------------------------------------------------
Center
Cell Value Surrounding Cell Values
(k5) (k1, k2,
k3, k4, k6, k7, k8, k9)
-----------------
--------------------------------------
Blur
POSITIVE Symmetrical
pattern of POSITIVE values
Sharpen POSITIVE Symmetrical pattern of
NEGATIVE values
Edges NEGATIVE Symmetrical pattern of POSITIVE values
Emboss
POSITIVE Symmetrical
pattern of NEGATIVE values
on
one side and POSITIVE values on the other
---------------------------------------------------------
Center Cell Value =
k5
Surrounding Cell
Values = k1, k2, k3, k4, k6, k7, k8, k9
Sum = (Center Cell
Value) + (Surrounding Cell Values)
Sum = k1 + k2 + k3 + k4 + k5 + k6 + k7 + k8 + k9
If Sum / Divisor = 1 ---> Retain the
brightness of the original image.
If Sum / Divisor
> 1 --->
Increases the bright of the image
If Sum / Divisor
< 1 --->
Darken the image
To reduce the
effect of a filter (Blur, Sharpen, Edges, etc.) you must increase the value of
the center cell (k5)
BT_BitmapTransform (hBitmap, Mode, Angle, aRGBColor_Fill_Bk)
Reflects and/or rotates of the specified bitmap and
returns a handle to the new transformed bitmap.
hBitmap: is a handle to the origin bitmap.
Mode: is one or a combination (sum) of the constants
BT_BITMAP_REFLECT_HORIZONTAL, BT_BITMAP_REFLECT_VERTICAL and BT_BITMAP_ROTATE (defined in BosTaurus.CH).
Angle: is the angle at which it is to rotate the image (range 0 to 360º).
This parameter is considered only if BT_BITMAP_ROTATE is set in Mode, otherwise it is ignored.
aRGBColor_Fill_Bk: array containing the RGB colors to fill the empty
spaces of the background of the image. This parameter is considered only if
BT_BITMAP_ROTATE is set in Mode,
otherwise it is ignored. For default: aRGBcolor_Fill_Bk = color of the first pixel of the origin
bitmap.
BT_BitmapCaptureDesktop (Row, Col, Width, Height)
Captures the desktop and returns a handle to the image
bitmap captured (hBitmap).
Row, Col, Width, Height: specifies the dimensions in pixels of the rectangle
to capture. For default: Row = 0, Col = 0, Width = BT_DesktopWidth(), Height = BT_DesktopHeight().
BT_BitmapCaptureWindow (Win, Row, Col, Width, Height)
Captures a specified window and returns a handle to
the image bitmap captured (hBitmap).
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
Row, Col, Width, Height: specifies the dimensions in pixels of the rectangle
to capture. For default: Row = 0, Col = 0, Width = BT_WindowWidth(Win), Height = BT_WindowHeight(Win).
BT_BitmapCaptureClientArea (Win, Row, Col, Width, Height)
Captures the client area of the specified window and
returns a handle to the image bitmap captured (hBitmap).
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window.
Row, Col, Width, Height: specifies the dimensions in pixels of the rectangle
to capture. For default: Row = 0, Col = 0, Width = BT_ClientAreaWidth(Win), Height = BT_ClientAreaHeight(Win).
BT_BitmapClipboardGet (Win)
Gets a bitmap image from the clipboard and returns a
handle to the bitmap (hBitmap). If the function fails
or the clipboard is empty returns zero.
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window associated to opening of the clipboard.
BT_BitmapClipboardPut (Win, hBitmap)
Put a bitmap image in the clipboard. If the function
fails returns FALSE (.F.), otherwise returns TRUE (.T.).
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window associated to opening of the clipboard.
hBitmap: is a handle to bitmap.
BT_BitmapClipboardClean (Win)
Empties the clipboard and frees all the handles of
data in the clipboard (bitmap, text, metafiles, etc.). If the function fails or
the clipboard is empty returns FALSE (.F.), otherwise returns TRUE (.T.).
Win: is the name (e.g. "Win1") or is the handle (e.g. hWin) of the window associated to opening of the clipboard.
BT_BitmapClipboardIsEmpty ()
Returns TRUE (.T.) if exist a bitmap image in the
clipboard, otherwise returns FALSE (.F.).
E) Functions
that Get/Release Handle Device Context
BT_CreateDC (Win_or_hBitmap, Type, @BTstruct)
Returns the handle to the device context specified (hDC).
Type: specifies the type of the handle device context to get, can be one of
the following constants: BT_HDC_DESKTOP (hDC to
desktop), BT_HDC_WINDOW (hDC to all window),
BT_HDC_ALLCLIENTAREA (hDC to the all client area),
BT_HDC_INVALIDCLIENTAREA (hDC
to the region of the client area that is not valid: invalid client area, i.e.
needs to be repainted) or BT_HDC_BITMAP (hDC to a
bitmap) (defined in BosTaurus.CH).
Win_or_hBitmap: is the name (e.g. "Win1") or is the handle
(e.g. hWin) to the window if Type is set as BT_HDC_WINDOW, BT_HDC_ALLCLIENTAREA or BT_HDC_INVALIDCLIENTAREA. Win_or_hBitmap is a handle to
bitmap (hBitmap) if Type is set as BT_HDC_BITMAP. If Type is set as BT_HDC_DESKTOP, Win_or_hBitmap is ignored.
BTstruct: is a variable (array) passed by reference that
stores information about the hDC obtained. This
information is necessary to properly release the hDC
obtained.
BT_DeleteDC (BTstruct)
Release from the memory a handle of device context.
BTstruct: is an array with information about a determined
handle of device context returned by BT_CreateDC function.
Remarks
The Bos
Taurus graphic library uses the common
Device Contexts (DC). The common DCs are Display
device contexts maintained in a special cache by the system. Because only a
limited number of common device contexts exist, an application should release
them after it has finished drawing. Because new display device contexts for the
cache are allocated in the application's heap space, failure to release the
device contexts eventually consumes all available heap space this causes an
error when it cannot allocate space for the new device context. This means that you should get the hDC, draw and then immediately release the hDC, do not store the hDC to
process other events drawing later.
The best way to process the ON PAINT event in HMG is
get the handle of the Device Context (hDC) of the
client area with Type =
BT_HDC_INVALIDCLIENTAREA in the BT_CreateDC function.
This way is fast for drawing and causes less display flicker that with
BT_HDC_ALLCLIENTAREA. The handle of the DC obtained with BT_HDC_ALLCLIENTAREA
is indicated to paint the client area out of the ON PAINT event.
F) Functions
for Drawing on a Device Context
BT_DrawGetPixel (hDC, Row, Col)
Gets RGB color value of the pixel at the specified
coordinates to the Device Context (DC) specified and returns a array with the color = {R,G,B}.
hDC: is a handle to the device context.
Row, Col: specifies the coordinates in pixels in the DC.
BT_DrawSetPixel (hDC, Row, Col, aRGBcolor)
Sets RGB color value of the pixel at the specified
coordinates to the Device Context (DC) specified.
hDC: is a handle to the device context.
Row, Col: specifies the coordinates in pixels in the DC.
aRGBcolor: is a array with the RGB
color = {R,G,B}.
BT_DrawBitmap (hDC, Row, Col, Width,
Height, Mode_Stretch, hBitmap)
Draws a bitmap in the Device Context (DC) specified.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the size of the rectangle in pixels in the
DC where you will draw the bitmap. For default: Row = 0, Col = 0, Width = BT_BitmapWidth(hBitmap), Height =
BT_BitmapHeight(hBitmap).
Mode_Stretch: sets the mode as the bitmap is adjusts (is stretches
or compresses) in the specified rectangle in the DC, it is one of the
constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in BosTaurus.CH).
hBitmap: is a handle to the bitmap.
BT_DrawBitmapTransparent (hDC, Row, Col, Width,
Height, Mode_Stretch, hBitmap,
aRGBcolor_transp)
Draws a transparent bitmap in the Device Context (DC)
specified.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the size of the rectangle in pixels in the
DC where you will draw the bitmap. For default: Row = 0, Col = 0, Width = BT_BitmapWidth(hBitmap), Height =
BT_BitmapHeight(hBitmap).
Mode_Stretch: sets the mode as the bitmap is adjusts (is stretches
or compresses) in the specified rectangle in the DC, it is one of the
constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in BosTaurus.CH).
hBitmap: is a handle to the bitmap.
aRGBcolor_transp: array containing the RGB colors to treat as
transparent in the bitmap. For default: aRGBcolor_transp =
color of the first pixel of the origin bitmap.
BT_DrawBitmapAlphaBlend (hDC, Row, Col, Width,
Height, Alpha, Mode_Stretch, hBitmap)
Draw a bitmap with Alpha Blend effect (that make the
pixels to be transparent or semi transparent) in the
Device Context (DC) specified.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the size of the rectangle in pixels in the
DC where you will draw the bitmap. For default: Row = 0, Col = 0, Width = BT_BitmapWidth(hBitmap), Height =
BT_BitmapHeight(hBitmap).
Alpha: is alpha blending value to be applied to the entire source bitmap (range 0
to 255, transparent = 0, opaque = 255).
Mode_Stretch: sets the mode as the bitmap is adjusts (is stretches
or compresses) in the specified rectangle in the DC, it is one of the
constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in BosTaurus.CH).
hBitmap: is a handle to the bitmap.
BT_DrawDCtoDC (hDC1, Row1, Col1, Width1, Height1, Mode_Stretch, hDC2, Row2, Col2, Width2, Height2)
Copy a rectangular area of a device context (origin)
in another device context (destination).
hDC1: is a handle to the destination device context.
Row1, Col1, Width1, Height1: specifies the size of the rectangle in pixels in the
destination DC where you will copy the origin DC.
Mode_Stretch: sets the mode as the rectangle in the origin DC is
adjusts (is stretches or compresses) in the specified rectangle in the destination
DC, it is one of the constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in
BosTaurus.CH).
hDC2: is a handle to the origin device context.
Row2, Col2, Width2, Height2: specifies the size of the rectangle in pixels in the
origin DC to copied in the destination DC.
BT_DrawDCtoDCTransparent (hDC1, Row1, Col1, Width1, Height1, Mode_Stretch, hDC2, Row2, Col2, Width2, Height2, aRGBcolor_transp)
Copy a transparent rectangular area of a device
context (origin) in another device context (destination).
hDC1: is a handle to the destination device context.
Row1, Col1, Width1, Height1: specifies the size of the rectangle in pixels in the
destination DC where you will copy the origin DC.
Mode_Stretch: sets the mode as the rectangle in the origin DC is
adjusts (is stretches or compresses) in the specified rectangle in the
destination DC, it is one of the constants: BT_SCALE, BT_STRETCH or BT_COPY
(defined in BosTaurus.CH).
hDC2: is a handle to the origin device context.
Row2, Col2, Width2, Height2: specifies the size of the rectangle in pixels in the
origin DC to copied in the destination DC.
aRGBcolor_transp: array containing the RGB colors to treat as
transparent in the origin DC. For default: aRGBcolor_transp = color of the first pixel of the
origin DC.
BT_DrawDCtoDCAlphaBlend (hDC1, Row1, Col1, Width1, Height1, Alpha, Mode_Stretch, hDC2, Row2, Col2, Width2, Height2)
Copy a rectangular area of a device context (origin)
with Alpha Blend effect (that make the pixels to be transparent or semi transparent) in another device context (destination).
hDC1: is a handle to the destination device context.
Row1, Col1, Width1, Height1: specifies the size of the rectangle in pixels in the
destination DC where you will copy the origin DC.
Alpha: is alpha blending value to be applied to the entire source bitmap (range 0
to 255, transparent = 0, opaque = 255).
Mode_Stretch: sets the mode as the rectangle in the origin DC is
adjusts (is stretches or compresses) in the specified rectangle in the destination
DC, it is one of the constants: BT_SCALE, BT_STRETCH or BT_COPY (defined in
BosTaurus.CH).
hDC2: is a handle to the origin device context.
Row2, Col2, Width2, Height2: specifies the size of the rectangle in pixels in the
origin DC to copied in the destination DC.
BT_DrawGradientFillHorizontal (hDC, Row, Col, Width,
Height, aColorRGBstart, aColorRGBend)
Fill a rectangular region from left to right
(horizontal) in a Device Context (DC) with a background color that is interpolated
from two colors specified.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the size of the rectangle in pixels in the
DC where it will be filled.
aColorRGBstart: array that contains the RGB colors with that will
begin filling. For default: aColorRGBstart = {0,0,0} = BLACK
aColorRGBend: array that contains the RGB colors with that will
end filling. For default: aColorRGBend = {255,255,255} = WHITE
BT_DrawGradientFillVertical (hDC, Row, Col, Width,
Height, aColorRGBstart, aColorRGBend)
Fill a rectangular region from top to bottom
(vertical) in a Device Context (DC) with a background color that is
interpolated from two colors specified.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the size of the rectangle in pixels in the
DC where it will be filled.
aColorRGBstart: array that contains the RGB colors with that will
begin filling. For default: aColorRGBstart = {255,255,255} = WHITE
aColorRGBend: array that contains the RGB colors with that will
end filling. For default: aColorRGBend = {0,0,0} = BLACK
BT_DrawText (hDC, Row, Col, cText, cFontName, nFontSize, aFontColor, aBackColor, nTypeText, nAlingText, nOrientation)
Write a character string in the Device Context (DC)
specified.
hDC: is a handle to the device context.
Row, Col: specifies the coordinates in pixels in the DC.
cText: is the text to draw.
cFontName: is the name of the font, e.g. “Times New Roman”
nFontSize: is the size of the font in logical units, e.g. 12.
aFontColor: array that contains the RGB colors that set the text
color. For default aFontColor
= {0,0,0} = BLACK
aBackColor: array that contains the RGB colors that set the
background text color. For default aBackColor = {255,255,255} = WHITE
nTypeText: sets if background fills (opaque) or not
(transparent) with the BackColor color before the
text it draws, it is one of the constants: BT_TEXT_OPAQUE or
BT_TEXT_TRANSPARENT (defined in BosTaurus.CH). The characteristic of the font
is set with one of the following constants: BT_TEXT_BOLD, BT_TEXT_ITALIC,
BT_TEXT_UNDERLINE, BT_TEXT_STRIKEOUT. For default: nTypeText =
BT_TEXT_OPAQUE.
nOrientation: sets the orientation of the text with respect of
specified coordinates in Col and Row (range -90 to +90º). In BosTaurus.CH
is defines some constants: BT_TEXT_NORMAL_ORIENTATION,
BT_TEXT_VERTICAL_ASCENDANT, BT_TEXT_VERTICAL_DESCENDANT,
BT_TEXT_DIAGONAL_ASCENDANT, BT_TEXT_DIAGONAL_DESCENDANT. For default nOrientation =
BT_TEXT_NORMAL_ORIENTATION.
Write a character string in a given rectangle in the
Device Context (DC) specified.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the size of the rectangle in pixels in the
DC where it will be written.
cText: is the text to draw.
cFontName: is the name of the font, e.g. “Times New Roman”
nFontSize: is the size of the font in logical units, e.g. 12.
aFontColor: array that contains the RGB colors that set the text
color. For default aFontColor
= {0,0,0} = BLACK
aBackColor: array that contains the RGB colors that set the
background text color. For default aBackColor = {255,255,255} = WHITE
nTypeText: sets if background fills (opaque) or not
(transparent) with the BackColor color before the
text it draws, it is one of the constants: BT_TEXT_OPAQUE or
BT_TEXT_TRANSPARENT (defined in BosTaurus.CH). The characteristic of the font
is set with one of the following constants: BT_TEXT_BOLD, BT_TEXT_ITALIC,
BT_TEXT_UNDERLINE, BT_TEXT_STRIKEOUT. For default: nTypeText =
BT_TEXT_OPAQUE.
nOrientation: sets the orientation of the text with respect of
specified coordinates in Col and Row (range -90 to +90º). In BosTaurus.CH
is defines some constants: BT_TEXT_NORMAL_ORIENTATION,
BT_TEXT_VERTICAL_ASCENDANT, BT_TEXT_VERTICAL_DESCENDANT,
BT_TEXT_DIAGONAL_ASCENDANT, BT_TEXT_DIAGONAL_DESCENDANT. For default nOrientation =
BT_TEXT_NORMAL_ORIENTATION.
BT_DrawTextSize (hDC, cText,
cFontName, nFontSize, nTypeText)
Gets the size in pixels of a string of characters for
the Device Context (DC) specified and returns an array with six elements: { nTextWidth, nTextHeight, A+B+C
of first character, A, B, C }.
Where: A spacing is the
distance added to the current position before placing the glyph. B
spacing is the width of the black part of the glyph. C spacing is the distance
added to the current position to provide white space to the right of the glyph.
The total advanced width is specified by A+B+C.
hDC: is a handle to the device context.
cText: is the text to get size.
cFontName: is the name of the font, e.g. “Times New Roman”
nFontSize: is the size of the font in logical units, e.g. 12.
nTypeText: is the characteristic of the font (BT_TEXT_BOLD,
BT_TEXT_ITALIC, BT_TEXT_UNDERLINE, BT_TEXT_STRIKEOUT).
BT_DrawPolyLine (hDC, aPointY,
aPointX, aColorRGBLine, nWidthLine)
Draws a series of line segments by connecting the
points the arrays specified.
hDC: is a handle to the device context.
aPointY: array containing the coordinates in pixels of the
points on the y-axis.
aPointX: array containing the coordinates in pixels of the
points on the x-axis.
aColorRGBLine: array that contains the RGB colors that set of the
lines color.
nWidthLine: width in pixels of the lines. For default: nWidthLine = 1.
Draws a polygon
consisting of two or more vertices connected by straight lines.
hDC: is a handle to the device context.
aPointY: array containing the coordinates in pixels of the
points on the y-axis.
aPointX: array containing the coordinates in pixels of the
points on the x-axis.
aColorRGBLine: array that contains the RGB colors that set of the
lines color.
nWidthLine: width in pixels of the lines. For default: nWidthLine = 1.
aColorRGBFill: array that contains
the RGB colors that set of the fill color.
BT_DrawPolyBezier (hDC, aPointY,
aPointX, aColorRGBLine, nWidthLine)
Draws one or more Bézier curves.
hDC: is a handle to the device context.
aPointY: array containing the coordinates in pixels of the points
on the y-axis.
aPointX: array containing the coordinates in pixels of the
points on the x-axis.
aColorRGBLine: array that contains the RGB colors that set of the
lines color.
nWidthLine: width in pixels of the lines. For default: nWidthLine = 1.
BT_DrawArc (hDC, Row1, Col1, Row2,
Col2, RowStartArc, ColStartArc, RowEndArc, ColEndArc, aColorRGBLine, nWidthLine)
Draws an elliptical arc.
hDC: is a handle to the device context.
Row1, Col1: specifies the upper-left corner of the bounding rectangle in
pixels.
Row2, Col2: specifies the lower-right corner of
the bounding rectangle in pixels.
RowStartArc, ColStartArc: specifies the ending point of the
radial line defining the starting point of the arc in pixels.
RowEndArc, ColEndArc: specifies the ending point of the
radial line defining the ending
point of the arc in pixels.
aColorRGBLine: array that contains the RGB colors that set of the
line color.
nWidthLine: width in pixels of the line. For default: nWidthLine = 1.
BT_DrawChord (hDC, Row1, Col1, Row2,
Col2, RowStartArc, ColStartArc, RowEndArc, ColEndArc, aColorRGBLine, nWidthLine, aColorRGBFill)
Draws a chord (a
region bounded by the intersection of an ellipse and a line segment, called a
secant).
hDC: is a handle to the device context.
Row1, Col1: specifies the upper-left corner of the bounding rectangle in
pixels.
Row2, Col2: specifies the lower-right corner of
the bounding rectangle in pixels.
RowStartArc, ColStartArc: specifies the ending point of the
radial line defining the starting point of the chord in pixels.
RowEndArc, ColEndArc: specifies the ending point of the
radial line defining the ending
point of the chord in pixels.
aColorRGBLine: array that contains the RGB colors that set of the
line color.
nWidthLine: width in pixels of the line. For default: nWidthLine = 1.
BT_DrawPie (hDC, Row1, Col1, Row2,
Col2, RowStartArc, ColStartArc, RowEndArc, ColEndArc, aColorRGBLine, nWidthLine, aColorRGBFill)
Draws a pie-shaped wedge bounded by the intersection
of an ellipse and two radials.
hDC: is a handle to the device context.
Row1, Col1: specifies the upper-left corner of the bounding rectangle in
pixels.
Row2, Col2: specifies the lower-right corner of
the bounding rectangle in pixels.
RowStartArc, ColStartArc: specifies the endpoint of the first radial in pixels.
RowEndArc, ColEndArc: specifies the endpoint of the second radial in pixels.
aColorRGBLine: array that contains the RGB colors that set of the
line color.
nWidthLine: width in pixels of the line. For default: nWidthLine = 1.
BT_DrawLine (hDC, Row1, Col1, Row2,
Col2, aColorRGBLine, nWidthLine)
Draw a line by connecting two points specified.
hDC: is a handle to the device context.
Row1, Col1: are the coordinates in pixels of the starting point.
Row2, Col2: are the coordinates in pixels of the end point.
aColorRGBLine: array that contains the RGB colors that set of the
line color.
nWidthLine: width in pixels of the line. For default: nWidthLine = 1.
BT_DrawRectangle (hDC, Row, Col, Width,
Height, aColorRGBLine, nWidthLine)
Draw a rectangle with the specified dimensions.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the
dimensions in pixels of the rectangle to be draw.
aColorRGBLine: array that contains the RGB colors that set of the
lines color.
nWidthLine: width in pixels of the lines. For default: nWidthLine = 1.
BT_DrawEllipse (hDC, Row1, Col1, Width,
Height, aColorRGBLine, nWidthLine)
Draw an ellipse with the specified dimensions.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the
dimensions in pixels of the ellipse to be draw.
aColorRGBLine: array that contains the RGB colors that set of the
line color.
nWidthLine: width in pixels of the line. For default: nWidthLine = 1.
BT_DrawFillRectangle (hDC, Row, Col, Width, Height,
aColorRGBFill, aColorRGBLine,
nWidthLine)
Draw a fill rectangle with the specified dimensions.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the
dimensions in pixels of the rectangle to be draw.
aColorRGBFill: array that contains
the RGB colors that set of the fill color.
aColorRGBLine: array that contains the RGB colors that set of the
lines color. For default: aColorRGBLine = aColorRGBFill.
nWidthLine: width in pixels of the lines. For default: nWidthLine = 1.
BT_DrawFillEllipse (hDC, Row, Col, Width,
Height, aColorRGBFill, aColorRGBLine,
nWidthLine)
Draw a fill ellipse with the specified dimensions.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the
dimensions in pixels of the ellipse to be draw.
aColorRGBFill: array that contains
the RGB colors that set of the fill color.
aColorRGBLine: array that contains the RGB colors that set of the
line color. For default: aColorRGBLine = aColorRGBFill.
nWidthLine: width in pixels of the line. For default: nWidthLine = 1.
BT_DrawFillRoundRect (hDC, Row, Col, Width,
Height, RoundWidth, RoundHeight,
aColorRGBFill, aColorRGBLine,
nWidthLine)
Draw a fill rectangle with rounded corners.
hDC: is a handle to the device context.
Row, Col, Width, Height: specifies the
dimensions in pixels of the rectangle to be draw.
RoundWidth: specifies the width in pixels of the ellipse used to
draw the rounded corners.
RoundHeight: specifies the height in pixels of the ellipse used
to draw the rounded corners.
aColorRGBFill: array that contains
the RGB colors that set of the fill color.
aColorRGBLine: array that contains the RGB colors that set of the
line color. For default: aColorRGBLine = aColorRGBFill.
nWidthLine: width in pixels of the line. For default: nWidthLine = 1.
BT_DrawFillFlood (hDC, Row, Col, aColorRGBFill)
Fill an area in all directions defined by the color of
the point of the specified coordinates.
hDC: is a handle to the device context.
Row, Col: specifies the coordinates in pixels of the point
where begin filling.
aColorRGBFill: array that contains
the RGB colors that set of the fill color.
G) Functions
of Connection Between HMG Controls and Bos Taurus
BT_HMGGetImage (cFormName, cControlName)
Returns the handle of the bitmap associated to an
Image Control of HMG (@...IMAGE).
cFormName: is the name (e.g. "Win1") of the parent
window.
cControlName: is the name (e.g. "Image1") of the image
control.
BT_ HMGCloneImage (cFormName, cControlName)
Clones the bitmap associated to an Image Control of
HMG (@...IMAGE) and returns a handle to the cloned bitmap.
cFormName: is the name (e.g. "Win1") of the parent
window.
cControlName: is the name (e.g. "Image1") of the image
control.
BT_HMGSetImage (cFormName, cControlName, hBitmap, lReleasePrevious)
Sets a specified bitmap into an Image Control of HMG
(@...IMAGE) and automatically releases the handle of the bitmap previously
associated to the Image Control.
cFormName: is the name (e.g. "Win1") of the parent
window.
cControlName: is the name (e.g. "Image1") of the image
control.
hBitmap: is a handle to the bitmap to set.
lReleasePrevious: releases of the hBitmap previous associate to Image Control. For default is
.T.
7) Bos Taurus: List of the Functions
