CDrawingManager Class
The CDrawingManager class implements complex drawing algorithms.
Syntax
class CDrawingManager : public CObject
Members
Public Constructors
| Name | Description |
|---|---|
| CDrawingManager::CDrawingManager | Constructs a CDrawingManager object. |
CDrawingManager::~CDrawingManager |
Destructor. |
Public Methods
| Name | Description |
|---|---|
| CDrawingManager::CreateBitmap_32 | Creates a 32-bit device-independent bitmap (DIB) that applications can write to directly. |
| CDrawingManager::DrawAlpha | Displays bitmaps that have transparent or semitransparent pixels. |
| CDrawingManager::DrawRotated | Rotates a source DC content inside the given rectangle by +/- 90 degrees |
| CDrawingManager::DrawEllipse | Draws an ellipse with the supplied fill and border colors. |
| CDrawingManager::DrawGradientRing | Draws a ring and fills it with a color gradient. |
| CDrawingManager::DrawLine, CDrawingManager::DrawLineA | Draws a line. |
| CDrawingManager::DrawRect | Draws a rectangle with the supplied fill and border colors. |
| CDrawingManager::DrawShadow | Draws a shadow for a rectangular area. |
| CDrawingManager::Fill4ColorsGradient | Fills a rectangular area with two color gradients. |
| CDrawingManager::FillGradient | Fills a rectangular area with a specified color gradient. |
| CDrawingManager::FillGradient2 | Fills a rectangular area with a specified color gradient. The direction of the gradient's color change is also specified. |
| CDrawingManager::GrayRect | Fills a rectangle with a specified gray color. |
| CDrawingManager::HighlightRect | Highlights a rectangular area. |
| CDrawingManager::HLStoRGB_ONE | Converts a color from a HLS representation to a RGB representation. |
| CDrawingManager::HLStoRGB_TWO | Converts a color from a HLS representation to a RGB representation. |
| CDrawingManager::HSVtoRGB | Converts a color from a HSV representation to a RGB representation. |
| CDrawingManager::HuetoRGB | Helper method that converts a hue value to a red, green, or blue component. |
| CDrawingManager::MirrorRect | Flips a rectangular area. |
| CDrawingManager::PixelAlpha | Helper method that determines the final color for a semitransparent pixel. |
| CDrawingManager::PrepareShadowMask | Creates a bitmap that can be used as a shadow. |
| CDrawingManager::RGBtoHSL | Converts a color from a RGB representation to a HSL representation. |
| CDrawingManager::RGBtoHSV | Converts a color from a RGB representation to a HSV representation. |
| CDrawingManager::SetAlphaPixel | Helper method that colors a partially transparent pixel in a bitmap. |
| CDrawingManager::SetPixel | Helper method that changes a single pixel in a bitmap to the specified color. |
| CDrawingManager::SmartMixColors | Combines two colors based on a weighted ratio. |
Remarks
The CDrawingManager class provides functions for drawing shadows, color gradients, and highlighted rectangles. It also performs alpha-blending. You can use this class to directly change your application's UI.
Inheritance Hierarchy
CObject
CDrawingManager
Requirements
Header: afxdrawmanager.h
CDrawingManager::CDrawingManager
Constructs a CDrawingManager object.
CDrawingManager(CDC& dc);
Parameters
dc
[in] A reference to a device context. The CDrawingManager uses this context for drawing.
CDrawingManager::CreateBitmap_32
Creates a 32-bit device-independent bitmap (DIB) that applications can write to directly.
static HBITMAP __stdcall CreateBitmap_32(
const CSize& size,
void** pBits);
static HBITMAP __stdcall CreateBitmap_32(
HBITMAP bitmap,
COLORREF clrTransparent = -1);
Parameters
size
[in] A CSize parameter that indicates the size of the bitmap.
pBits
[out] A pointer to a data pointer that receives the location of the DIB's bit values.
bitmap
A handle to the original bitmap
clrTransparent
An RGB value specifying transparent color of the original bitmap.
Return Value
A handle to the newly created DIB bitmap if this method is successful; otherwise NULL.
Remarks
For more information about how to create a DIB bitmap, see CreateDIBSection.
CDrawingManager::DrawAlpha
Displays bitmaps that have transparent or semitransparent pixels.
void DrawAlpha(
CDC* pDstDC,
const CRect& rectDst,
CDC* pSrcDC,
const CRect& rectSrc);
Parameters
pDstDC
[in] A pointer to the device context for the destination.
rectDst
[in] The destination rectangle.
pSrcDC
[in] A pointer to the device context for the source.
rectSrc
[in] The source rectangle.
Remarks
This method performs alpha-blending for two bitmaps. For more information about alpha-blending, see AlphaBlend in the Windows SDK.
CDrawingManager::DrawEllipse
Draws an ellipse with the supplied fill and border colors.
void DrawEllipse(
const CRect& rect,
COLORREF clrFill,
COLORREF clrLine);
Parameters
rect
[in] The bounding rectangle for the ellipse.
clrFill
[in] The color this method uses to fill the ellipse.
clrLine
[in] The color this method uses as the border of the ellipse.
Remarks
This method returns without drawing an ellipse if either color is set to -1. It also returns without drawing an ellipse if either dimension of the bounding rectangle is 0.
CDrawingManager::DrawGradientRing
Draws a ring and fills it with a color gradient.
BOOL DrawGradientRing(
CRect rect,
COLORREF colorStart,
COLORREF colorFinish,
COLORREF colorBorder,
int nAngle,
int nWidth,
COLORREF clrFace = (COLORREF)-1);
Parameters
rect
[in] A CRect parameter that specifies the boundary for the gradient ring.
colorStart
[in] The first color for the gradient.
colorFinish
[in] The last color for the gradient.
colorBorder
[in] The color of the border.
nAngle
[in] A parameter that specifies the initial gradient drawing angle. This value should be between 0 and 360.
nWidth
[in] The width of the border for the ring.
clrFace
[in] The color of the interior of the ring.
Return Value
Nonzero if successful; otherwise 0.
Remarks
The rectangle defined by rect must be at least 5 pixels wide and 5 pixels high.
CDrawingManager::DrawLine, CDrawingManager::DrawLineA
Draws a line.
void DrawLine(
int x1,
int y1,
int x2,
int y2,
COLORREF clrLine);
void DrawLineA(
double x1,
double y1,
double x2,
double y2,
COLORREF clrLine);
Parameters
x1
[in] The x coordinate where the line starts.
y1
[in] The y coordinate where the line starts.
x2
[in] The x coordinate where the line ends.
y2
[in] The y coordinate where the line ends.
clrLine
[in] The color of the line.
Remarks
This method fails if clrLine equals -1.
CDrawingManager::DrawRect
Draws a rectangle with the supplied fill and border colors.
void DrawRect(
const CRect& rect,
COLORREF clrFill,
COLORREF clrLine);
Parameters
rect
[in] The boundaries for the rectangle.
clrFill
[in] The color this method uses to fill the rectangle.
clrLine
[in] The color this method uses for the border of the rectangle.
Remarks
This method returns without drawing a rectangle if either color is set to -1. It also returns if either dimension of the rectangle is 0.
CDrawingManager::DrawShadow
Draws a shadow for a rectangular area.
BOOL DrawShadow(
CRect rect,
int nDepth,
int iMinBrightness = 100,
int iMaxBrightness = 50,
CBitmap* pBmpSaveBottom = NULL,
CBitmap* pBmpSaveRight = NULL,
COLORREF clrBase = (COLORREF)-1,
BOOL bRightShadow = TRUE);
Parameters
rect
[in] A rectangular area in your application. The drawing manager will draw a shadow underneath this area.
nDepth
[in] The width and height of the shadow.
iMinBrightness
[in] The minimum brightness of the shadow.
iMaxBrightness
[in] The maximum brightness of the shadow.
pBmpSaveBottom
[in] A pointer to a bitmap that contains the image for the bottom part of the shadow.
pBmpSaveRight
[in] A pointer to a bitmap that contains the image for the shadow that is drawn on the right side of the rectangle.
clrBase
[in] The color of the shadow.
bRightShadow
[in] A Boolean parameter that indicates how the shadow is drawn. If bRightShadow is TRUE, DrawShadow draws a shadow on the right side of the rectangle.
Return Value
Nonzero if successful; otherwise 0.
Remarks
You can provide two valid bitmaps for the bottom and right shadows by using the parameters pBmpSaveBottom and pBmpSaveRight. If these CBitmap objects have an attached GDI object, DrawShadow will use those bitmaps as the shadows. If the CBitmap parameters do not have an attached GDI object, DrawShadow draws the shadow and attaches the bitmaps to the parameters. In future calls to DrawShadow, you can provide these bitmaps to speed up the drawing process. For more information about the CBitmap class and GDI objects, see Graphic Objects.
If either of these parameters is NULL, DrawShadow will automatically draw the shadow.
If you set bRightShadow to FALSE, the shadow will be drawn underneath and to the left of the rectangular area.
Example
The following example demonstrates how to use the DrawShadow method of the CDrawingManager class. This code snippet is part of the Prop Sheet Demo sample.
// CDC* pDC
// CRect rectHeader
CDrawingManager dm(*pDC);
// Draw a shadow for a rectangular area.
// second parameter is the depth of the shadow
dm.DrawShadow(rectHeader, 2);
CDrawingManager::Fill4ColorsGradient
Fills a rectangular area with two color gradients.
void Fill4ColorsGradient(
CRect rect,
COLORREF colorStart1,
COLORREF colorFinish1,
COLORREF colorStart2,
COLORREF colorFinish2,
BOOL bHorz = TRUE,
int nPercentage = 50);
Parameters
rect
[in] The rectangle to fill.
colorStart1
[in] The initial color for the first color gradient.
colorFinish1
[in] The final color for the first color gradient.
colorStart2
[in] The initial color for the second color gradient.
colorFinish2
[in] The final color for the second color gradient.
bHorz
[in] A Boolean parameter that indicates whether Fill4ColorsGradient colors a horizontal or vertical gradient. TRUE indicates a horizontal gradient.
nPercentage
[in] An integer from 0-100. This value indicates the percentage of the rectangle to fill with the first color gradient.
Remarks
When a rectangle is filled with two color gradients, they are either located above each other or next to each other, depending on the value of bHorz. Each color gradient is calculated independently with the method CDrawingManager::FillGradient.
This method generates an assertion failure if nPercentage is less than 0 or more than 100.
CDrawingManager::FillGradient
Fills a rectangular area with the specified color gradient.
void FillGradient(
CRect rect,
COLORREF colorStart,
COLORREF colorFinish,
BOOL bHorz = TRUE,
int nStartFlatPercentage = 0,
int nEndFlatPercentage = 0);
Parameters
rect
[in] The rectangular area to fill.
colorStart
[in] The first color for the gradient.
colorFinish
[in] The final color for the gradient.
bHorz
[in] A Boolean parameter that specifies whether FillGradient should draw a horizontal or vertical gradient.
nStartFlatPercentage
[in] The percentage of the rectangle that FillGradient fills with colorStart before it starts the gradient.
nEndFlatPercentage
[in] The percentage of the rectangle that FillGradient fills with colorFinish after it finishes the gradient.
Example
The following example demonstrates how to use the FillGradient method of the CDrawingManager class. This code snippet is part of the MS Office 2007 Demo sample.
// CRect rectScreen
// CDrawingManager dm
dm.FillGradient(rectScreen, RGB(114, 125, 152), RGB(178, 185, 202), TRUE);
CDrawingManager::FillGradient2
Fills a rectangular area with a specified color gradient.
void FillGradient2 (
CRect rect,
COLORREF colorStart,
COLORREF colorFinish,
int nAngle = 0);
Parameters
rect
[in] The rectangular area to fill.
colorStart
[in] The first color of the gradient.
colorFinish
[in] The last color of the gradient.
nAngle
[in] An integer between 0 and 360. This parameter specifies the direction of the color gradient.
Remarks
Use nAngle to specify the direction of the color gradient. When you specify the direction of the color gradient, you also specify where the color gradient starts. A value of 0 for nAngle indicates the gradient starts from the top of the rectangle. As nAngle increases, the starting location for the gradient moves in a counter-clockwise direction based on the angle.
Example
The following example demonstrates how to use the FillGradient2 method of the CDrawingManager class. This code snippet is part of the New Controls sample.
// CRect rect
// CDC* pDC
CDrawingManager dm(*pDC);
// The last parameter is the angle that specifies the direction of the color gradient.
dm.FillGradient2(rect, RGB(102, 200, 238), RGB(0, 129, 185), 45);
CDrawingManager::GrayRect
Fills a rectangle with a specified gray color.
BOOL GrayRect(
CRect rect,
int nPercentage = -1,
COLORREF clrTransparent = (COLORREF)-1,
COLORREF clrDisabled = (COLORREF)-1);
Parameters
rect
[in] The rectangular area to fill.
nPercentage
[in] The percentage of gray you want in the rectangle.
clrTransparent
[in] The transparent color.
clrDisabled
[in] The color that this method uses for de-saturation if nPercentage is set to -1.
Return Value
TRUE if the method was successful; otherwise FALSE.
Remarks
For the parameter nPercentage, a lower value indicates a darker color.
The maximum value for nPercentage is 200. A value larger than 200 does not change the appearance of the rectangle. If the value is -1, this method uses clrDisabled to limit the saturation of the rectangle.
CDrawingManager::HighlightRect
Highlights a rectangular area.
BOOL HighlightRect(
CRect rect,
int nPercentage = -1,
COLORREF clrTransparent = (COLORREF)-1,
int nTolerance = 0,
COLORREF clrBlend = (COLORREF)-1);
Parameters
rect
[in] A rectangular area to highlight.
nPercentage
[in] A percentage that indicates how transparent the highlight should be.
clrTransparent
[in] The transparent color.
nTolerance
[in] An integer between 0 and 255 that indicates the color tolerance.
clrBlend
[in] The base color for blending.
Return Value
TRUE if the method is successful; otherwise FALSE.
Remarks
If nPercentage is between 0 and 99, HighlightRect uses the alpha blending algorithm. For more information about alpha blending, see Alpha Blending Lines and Fills. If nPercentage is -1, this method uses the default highlight level. If nPercentage is 100, this method does nothing and returns TRUE.
The method uses the parameter nTolerance to determine whether to highlight the rectangular area. To highlight the rectangle, the difference between the background color of your application and clrTransparent must be less than nTolerance in each color component (red, green, and blue).
CDrawingManager::HLStoRGB_ONE
Converts a color from a HLS representation to a RGB representation.
static COLORREF __stdcall HLStoRGB_ONE(
double H,
double L,
double S);
Parameters
H
[in] A number between 0 and 1 that represents the hue for the color.
L
[in] A number between 0 and 1 that indicates the luminosity for the color.
S
[in] A number between 0 and 1 that indicates the saturation for the color.
Return Value
The RGB representation of the HLS color provided.
Remarks
A color can be represented as HSV (hue, saturation, and value), HSL (hue, saturation, and luminosity), or RGB (red, green, and blue). For more information about the different representations of color, see Color.
This method and the CDrawingManager::HLStoRGB_TWO method perform the same operation, but require different values for the H parameter. In this method, H is a percentage of the circle. In the CDrawingManager::HLStoRGB_TWO method, H is a degree value between 0 and 360, which both represent red. For example, with HLStoRGB_ONE, a value of 0.25 for H is equivalent to a value of 90 with HLStoRGB_TWO.
CDrawingManager::HLStoRGB_TWO
Converts a color from a HLS representation to a RGB representation.
static COLORREF __stdcall HLStoRGB_TWO(
double H,
double L,
double S);
Parameters
H
[in] A number between 0 and 360 that represents the hue for the color.
L
[in] A number between 0 and 1 that indicates the luminosity for the color.
S
[in] A number between 0 and 1 that indicates the saturation for the color.
Return Value
The RGB representation of the HLS color provided.
Remarks
A color can be represented as HSV (hue, saturation, and value), HSL (hue, saturation, and luminosity), or RGB (red, green, and blue). For more information about the different representations of color, see Color.
This method and the CDrawingManager::HLStoRGB_ONE method perform the same operation, but require different values for the H parameter. In this method, H is a degree value between 0 and 360, which both represent red. In the CDrawingManager::HLStoRGB_ONE method, H is a percentage of the circle. For example, with HLStoRGB_ONE, a value of 0.25 for H is equivalent to a value of 90 with HLStoRGB_TWO.
CDrawingManager::HSVtoRGB
Converts a color from a HSV representation to a RGB representation.
static COLORREF __stdcall HSVtoRGB(
double H,
double S,
double V);
Parameters
H
[in] A number between 0 and 360 that indicates the hue for the color.
S
[in] A number between 0 and 1 that indicates the saturation for the color.
V
[in] A number between 0 and 1 that indicates the value for the color.
Return Value
The RGB representation of the HSV color provided.
Remarks
A color can be represented as HSV (hue, saturation, and value), HSL (hue, saturation, and luminosity), or RGB (red, green, and blue). For more information about the different representations of color, see Color.
CDrawingManager::HuetoRGB
Converts a hue value to a red, green, or blue component.
static double __stdcall HuetoRGB(
double m1,
double m2,
double h);
static BYTE __stdcall HueToRGB(
float rm1,
float rm2,
float rh);
Parameters
m1
[in] See Remarks.
m2
[in] See Remarks.
h
[in] See Remarks.
rm1
[in] See Remarks.
rm2
[in] See Remarks.
rh
[in] See Remarks.
Return Value
The individual red, green, or blue component for the provided hue.
Remarks
This method is a helper method that the CDrawingManager class uses to compute the individual red, green, and blue components of a color in a HSV or HSL representation. This method is not designed to be called directly by the programmer. The input parameters are values that depend on the conversion algorithm.
To convert a HSV or HSL color to a RGB representation, call one of the following methods:
CDrawingManager::MirrorRect
Flips a rectangular area.
void MirrorRect(
CRect rect,
BOOL bHorz = TRUE);
Parameters
rect
[in] The bounding rectangle of the area to flip.
bHorz
[in] A Boolean parameter that indicates whether the rectangle flips horizontally or vertically.
Remarks
This method can flip any area of the device context owned by the CDrawingManager class. If bHorz is set to TRUE, this method flips the area horizontally. Otherwise, it flips the area vertically.
CDrawingManager::PixelAlpha
Calculates the final color for a semitransparent pixel.
static COLORREF __stdcall PixelAlpha(
COLORREF srcPixel,
int percent);
static COLORREF __stdcall PixelAlpha(
COLORREF srcPixel,
double percentR,
double percentG,
double percentB);
static COLORREF __stdcall PixelAlpha(
COLORREF srcPixel,
COLORREF dstPixel,
int percent);
Parameters
srcPixel
[in] The initial color for the pixel.
percent
[in] A number between 0 and 100 that represents the percentage of transparency. A value of 100 indicates that the initial color is completely transparent.
percentR
[in] A number between 0 and 100 that represents the percentage of transparency for the red component.
percentG
[in] A number between 0 and 100 that represents the percentage of transparency for the green component.
percentB
[in] A number between 0 and 100 that represents the percentage of transparency for the blue component.
dstPixel
[in] The base color for the pixel.
Return Value
The final color for the semitransparent pixel.
Remarks
This is a helper class for coloring semitransparent bitmaps and is not designed to be called directly by the programmer.
When you use the version of the method that has dstPixel, the final color is a combination of dstPixel and srcPixel. The srcPixel color is the partially transparent color over the base color of dstPixel.
CDrawingManager::PrepareShadowMask
Creates a bitmap that can be used as a shadow.
static HBITMAP __stdcall PrepareShadowMask (
int nDepth,
COLORREF clrBase,
int iMinBrightness = 0,
int iMaxBrightness = 100);
Parameters
nDepth
[in] The width and height of the shadow.
clrBase
[in] The color of the shadow.
iMinBrightness
[in] The minimum brightness of the shadow.
iMaxBrightness
[in] The maximum brightness of the shadow.
Return Value
A handle to the created bitmap if this method is successful; otherwise NULL.
Remarks
If nDepth is set to 0, this method exits and returns NULL. If nDepth is less than 3, the width and height of the shadow are set to 3 pixels.
CDrawingManager::RGBtoHSL
Converts a color from a red, green, and blue (RGB) representation to a hue, saturation, and lightness (HSL) representation.
static void __stdcall RGBtoHSL(
COLORREF rgb,
double* H,
double* S,
double* L);
Parameters
rgb
[in] The color in RGB values.
H
[out] A pointer to a double where the method stores the hue for the color.
S
[out] A pointer to a double where the method stores the saturation for the color.
L
[out] A pointer to a double where the method stores the lightness for the color.
Remarks
A color can be represented as HSV (hue, saturation, and value), HSL (hue, saturation, and luminosity), or RGB (red, green, and blue). For more information about the different representations of color, see Color.
The returned value for H is represented as a fraction between 0 and 1 where both 0 and 1 represent red. The returned values for S and L are numbers between 0 and 1.
CDrawingManager::RGBtoHSV
Converts a color from a RGB representation to a HSV representation.
static void __stdcall RGBtoHSV(
COLORREF rgb,
double* H,
double* S,
double* V);
Parameters
rgb
[in] The color to convert in a RGB representation.
H
[out] A pointer to a double where this method stores the resulting hue for the color.
S
[out] A pointer to a double where this method stores the resulting saturation for the color.
V
[out] A pointer to a double where this method stores the resulting value for the color.
Remarks
A color can be represented as HSV (hue, saturation, and value), HSL (hue, saturation, and luminosity), or RGB (red, green, and blue). For more information about the different representations of color, see Color.
The returned value for H is a number between 0 and 360 where both 0 and 360 indicate red. The return values for S and V are numbers between 0 and 1.
CDrawingManager::SetAlphaPixel
Colors a transparent pixel in a bitmap.
static void __stdcall SetAlphaPixel(
COLORREF* pBits,
CRect rect,
int x,
int y,
int percent,
int iShadowSize,
COLORREF clrBase = (COLORREF)-1,
BOOL bIsRight = TRUE);
Parameters
pBits
[in] A pointer to the bit values for the bitmap.
rect
[in] A rectangular area in your application. The drawing manager draws a shadow underneath and to the right of this area.
x
[in] The horizontal coordinate of the pixel to color.
y
[in] The vertical coordinate of the pixel to color.
percent
[in] The percentage of transparency.
iShadowSize
[in] The width and height of the shadow.
clrBase
[in] The color of the shadow.
bIsRight
[in] A Boolean parameter that indicates which pixel to color. See the Remarks section for more information.
Remarks
This method is a helper method that is used by the CDrawingManager::DrawShadow method. We recommend that if you want to draw a shadow, call CDrawingManager::DrawShadow instead.
If bIsRight is set to TRUE, the pixel to color is measured x pixels from the right edge of rect. If it is FALSE, the pixel to color is measured x pixels from the left edge of rect.
CDrawingManager::SetPixel
Changes a single pixel in a bitmap to the specified color.
static void __stdcall SetPixel(
COLORREF* pBits,
int cx,
int cy,
int x,
int y,
COLORREF color);
Parameters
pBits
[in] A pointer to the bit values of the bitmap.
cx
[in] The total width of the bitmap.
cy
[in] The total height of the bitmap.
x
[in] The x-coordinate of the pixel in the bitmap to change.
y
[in] The y-coordinate of the pixel in the bitmap to change.
color
[in] The new color for the pixel identified by the supplied coordinates.
CDrawingManager::SmartMixColors
Combines two colors based on a weighted ratio.
static COLORREF __stdcall SmartMixColors(
COLORREF color1,
COLORREF color2,
double dblLumRatio = 1.,
int k1 = 1,
int k2 = 1);
Parameters
color1
[in] The first color to mix.
color2
[in] The second color to mix.
dblLumRatio
[in] The ratio for the new color's luminosity. SmartMixColors multiplies the luminosity of the mixed color by this ratio before determining a final color.
k1
[in] The weighted ratio for the first color.
k2
[in] The weighted ratio for the second color.
Return Value
A color that represents a weighted mixture of the supplied colors.
Remarks
This method fails with an error if either k1 or k2 is less than zero. If both of these parameters are set to 0, the method returns RGB(0, 0, 0).
The weighted ratio is calculated with the following formula: (color1 * k1 + color2 * k2)/(k1 + k2). After the weighted ratio is determined, the method calculates the luminosity for the mixed color. It then multiplies the luminosity by dblLumRatio. If the value is larger than 1.0, the method sets the luminosity for the mixed color to the new value. Otherwise, the luminosity is set to 1.0.
CDrawingManager::DrawRotated
Rotates a source DC content inside the given rectangle by 90 degrees.
void DrawRotated(
CRect rectDest,
CDC& dcSrc,
BOOL bClockWise);
Parameters
rectDest
Destination rectangle.
dcSrc
The source device context.
bClockWise
TRUE indicates rotate +90 degrees; FALSE indicates rotate -90 degrees.