Helper functions that support graphics operations. More...

Functions
bool	gslc_IsInRect (int16_t nSelX, int16_t nSelY, gslc_tsRect rRect)
	Determine if a coordinate is inside of a rectangular region. More...

gslc_tsRect	gslc_ExpandRect (gslc_tsRect rRect, int16_t nExpandW, int16_t nExpandH)
	Expand or contract a rectangle in width and/or height (equal amounts on both side), based on the centerpoint of the rectangle. More...

bool	gslc_IsInWH (int16_t nSelX, int16_t nSelY, uint16_t nWidth, uint16_t nHeight)
	Determine if a coordinate is inside of a width x height region. More...

void	gslc_UnionRect (gslc_tsRect *pRect, gslc_tsRect rAddRect)
	Expand a rect to include another rect. More...

void	gslc_InvalidateRgnReset (gslc_tsGui *pGui)
	Reset the invalidation region. More...

void	gslc_InvalidateRgnPage (gslc_tsGui pGui, gslc_tsPage pPage)
	Include an entire page (eg. More...

void	gslc_InvalidateRgnScreen (gslc_tsGui *pGui)
	Mark the entire screen as invalidated. More...

void	gslc_InvalidateRgnAdd (gslc_tsGui *pGui, gslc_tsRect rAddRect)
	Add a rectangular region to the invalidation region. More...

bool	gslc_ClipPt (gslc_tsRect *pClipRect, int16_t nX, int16_t nY)
	Perform basic clipping of a single point to a clipping region. More...

bool	gslc_ClipLine (gslc_tsRect pClipRect, int16_t pnX0, int16_t pnY0, int16_t pnX1, int16_t *pnY1)
	Perform basic clipping of a line to a clipping region. More...

bool	gslc_ClipRect (gslc_tsRect pClipRect, gslc_tsRect pRect)
	Perform basic clipping of a rectangle to a clipping region. More...

gslc_tsImgRef	gslc_GetImageFromFile (const char *pFname, gslc_teImgRefFlags eFmt)
	Create an image reference to a bitmap file in LINUX filesystem. More...

gslc_tsImgRef	gslc_GetImageFromSD (const char *pFname, gslc_teImgRefFlags eFmt)
	Create an image reference to a bitmap file in SD card. More...

gslc_tsImgRef	gslc_GetImageFromRam (unsigned char *pImgBuf, gslc_teImgRefFlags eFmt)
	Create an image reference to a bitmap in SRAM. More...

gslc_tsImgRef	gslc_GetImageFromProg (const unsigned char *pImgBuf, gslc_teImgRefFlags eFmt)
	Create an image reference to a bitmap in program memory (PROGMEM) More...

void	gslc_PolarToXY (uint16_t nRad, int16_t n64Ang, int16_t nDX, int16_t nDY)
	Convert polar coordinate to cartesian. More...

int16_t	gslc_sinFX (int16_t n64Ang)
	Calculate fixed-point sine function from fractional degrees. More...

int16_t	gslc_cosFX (int16_t n64Ang)
	Calculate fixed-point cosine function from fractional degrees. More...

gslc_tsColor	gslc_ColorBlend2 (gslc_tsColor colStart, gslc_tsColor colEnd, uint16_t nMidAmt, uint16_t nBlendAmt)
	Create a color based on a blend between two colors. More...

gslc_tsColor	gslc_ColorBlend3 (gslc_tsColor colStart, gslc_tsColor colMid, gslc_tsColor colEnd, uint16_t nMidAmt, uint16_t nBlendAmt)
	Create a color based on a blend between three colors. More...

bool	gslc_ColorEqual (gslc_tsColor a, gslc_tsColor b)
	Check whether two colors are equal. More...

Detailed Description

Helper functions that support graphics operations.

Function Documentation

bool gslc_ClipLine	(	gslc_tsRect *	pClipRect,
		int16_t *	pnX0,
		int16_t *	pnY0,
		int16_t *	pnX1,
		int16_t *	pnY1
	)

Perform basic clipping of a line to a clipping region.

Implements Cohen-Sutherland algorithm
Coordinates in parameter list are modified to fit the region

Parameters

[in]	pClipRect	Pointer to clipping region
[in,out]	pnX0	Ptr to X coordinate of line start
[in,out]	pnY0	Ptr to Y coordinate of line start
[in,out]	pnX1	Ptr to X coordinate of line end
[in,out]	pnY1	Ptr to Y coordinate of line end

Returns: true if line is visible, false if it should be discarded

bool gslc_ClipPt	(	gslc_tsRect *	pClipRect,
		int16_t	nX,
		int16_t	nY
	)

Perform basic clipping of a single point to a clipping region.

Parameters

[in]	pClipRect	Pointer to clipping region
[in]	nX	X coordinate of point
[in]	nY	Y coordinate of point

Returns: true if point is visible, false if it should be discarded

bool gslc_ClipRect	(	gslc_tsRect *	pClipRect,
		gslc_tsRect *	pRect
	)

Perform basic clipping of a rectangle to a clipping region.

Coordinates in parameter rect are modified to fit the region

Parameters

[in]	pClipRect	Pointer to clipping region
[in,out]	pRect	Ptr to rectangle

Returns: true if rect is visible, false if it should be discarded

gslc_tsColor gslc_ColorBlend2	(	gslc_tsColor	colStart,
		gslc_tsColor	colEnd,
		uint16_t	nMidAmt,
		uint16_t	nBlendAmt
	)

Create a color based on a blend between two colors.

Parameters

[in]	colStart	Starting color
[in]	colEnd	Ending color
[in]	nMidAmt	Position (0..1000) between start and end color at which the midpoint between colors should appear. Normally set to 500 (half-way).
[in]	nBlendAmt	The position (0..1000) between start and end at which we want to calculate the resulting blended color.

Returns: Blended color

gslc_tsColor gslc_ColorBlend3	(	gslc_tsColor	colStart,
		gslc_tsColor	colMid,
		gslc_tsColor	colEnd,
		uint16_t	nMidAmt,
		uint16_t	nBlendAmt
	)

Create a color based on a blend between three colors.

Parameters

[in]	colStart	Starting color
[in]	colMid	Intermediate color
[in]	colEnd	Ending color
[in]	nMidAmt	Position (0..1000) between start and end color at which the intermediate color should appear.
[in]	nBlendAmt	The position (0..1000) between start and end at which we want to calculate the resulting blended color.

Returns: Blended color

bool gslc_ColorEqual	(	gslc_tsColor	a,
		gslc_tsColor	b
	)

Check whether two colors are equal.

Parameters

[in]	a	First color
[in]	b	Second color

Returns: True iff a and b are the same color.

int16_t gslc_cosFX ( int16_t n64Ang )

Calculate fixed-point cosine function from fractional degrees.

Depending on configuration, the result is derived from either floating point math library or fixed point lookup table.
gslc_cosFX(nAngDeg*64)/32768.0 = cos(nAngDeg*2pi/360)

Parameters

[in] n64Ang Angle (in units of 1/64 degrees)

Returns: Fixed-point cosine result. Signed 16-bit; divide by 32768 to get the actual value.

gslc_tsRect gslc_ExpandRect	(	gslc_tsRect	rRect,
		int16_t	nExpandW,
		int16_t	nExpandH
	)

Expand or contract a rectangle in width and/or height (equal amounts on both side), based on the centerpoint of the rectangle.

Parameters

[in]	rRect	Rectangular region before resizing
[in]	nExpandW	Number of pixels to expand the width (if positive) of contract the width (if negative)
[in]	nExpandH	Number of pixels to expand the height (if positive) of contract the height (if negative)

Returns: gslc_tsRect() with resized dimensions

gslc_tsImgRef gslc_GetImageFromFile	(	const char *	pFname,
		gslc_teImgRefFlags	eFmt
	)

Create an image reference to a bitmap file in LINUX filesystem.

Parameters

[in]	pFname	Pointer to filename string of image in filesystem
[in]	eFmt	Image format

Returns: Loaded image reference

gslc_tsImgRef gslc_GetImageFromProg	(	const unsigned char *	pImgBuf,
		gslc_teImgRefFlags	eFmt
	)

Create an image reference to a bitmap in program memory (PROGMEM)

Parameters

[in]	pImgBuf	Pointer to image buffer in memory
[in]	eFmt	Image format

Returns: Loaded image reference

gslc_tsImgRef gslc_GetImageFromRam	(	unsigned char *	pImgBuf,
		gslc_teImgRefFlags	eFmt
	)

Create an image reference to a bitmap in SRAM.

Parameters

[in]	pImgBuf	Pointer to image buffer in memory
[in]	eFmt	Image format

Returns: Loaded image reference

gslc_tsImgRef gslc_GetImageFromSD	(	const char *	pFname,
		gslc_teImgRefFlags	eFmt
	)

Create an image reference to a bitmap file in SD card.

Parameters

[in]	pFname	Pointer to filename string of image in SD card
[in]	eFmt	Image format

Returns: Loaded image reference

void gslc_InvalidateRgnAdd	(	gslc_tsGui *	pGui,
		gslc_tsRect	rAddRect
	)

Add a rectangular region to the invalidation region.

This is usually called when an element has been modified

Parameters

[in]	pGui	Pointer to GUI
[in]	rAddRect	Rectangle to add to the invalidation region

Returns: none

void gslc_InvalidateRgnPage	(	gslc_tsGui *	pGui,
		gslc_tsPage *	pPage
	)

Include an entire page (eg.

from a page stack) in the invalidation region

Parameters

[in]	pGui	Pointer to GUI
[in]	pPage	Pointer to page

Returns: none

void gslc_InvalidateRgnReset ( gslc_tsGui * pGui )

Reset the invalidation region.

Parameters

[in] pGui Pointer to GUI

Returns: none

void gslc_InvalidateRgnScreen ( gslc_tsGui * pGui )

Mark the entire screen as invalidated.

Parameters

[in] pGui Pointer to GUI

Returns: none

bool gslc_IsInRect	(	int16_t	nSelX,
		int16_t	nSelY,
		gslc_tsRect	rRect
	)

Determine if a coordinate is inside of a rectangular region.

This routine is useful in determining if a touch coordinate is inside of a button.

Parameters

[in]	nSelX	X coordinate to test
[in]	nSelY	X coordinate to test
[in]	rRect	Rectangular region to compare against

Returns: true if inside region, false otherwise

bool gslc_IsInWH	(	int16_t	nSelX,
		int16_t	nSelY,
		uint16_t	nWidth,
		uint16_t	nHeight
	)

Determine if a coordinate is inside of a width x height region.

This routine is useful in determining if a relative coordinate is within a given W x H dimension

Parameters

[in]	nSelX	X coordinate to test
[in]	nSelY	X coordinate to test
[in]	nWidth	Width to test against
[in]	nHeight	Height to test against

Returns: true if inside region, false otherwise

void gslc_PolarToXY	(	uint16_t	nRad,
		int16_t	n64Ang,
		int16_t *	nDX,
		int16_t *	nDY
	)

Convert polar coordinate to cartesian.

Parameters

[in]	nRad	Radius of ray
[in]	n64Ang	Angle of ray (in units of 1/64 degrees, 0 is up)
[out]	nDX	X offset for ray end
[out]	nDY	Y offset for ray end

Returns: none

int16_t gslc_sinFX ( int16_t n64Ang )

Calculate fixed-point sine function from fractional degrees.

Depending on configuration, the result is derived from either floating point math library or fixed point lookup table.
gslc_sinFX(nAngDeg*64)/32768.0 = sin(nAngDeg*2pi/360)

Parameters

[in] n64Ang Angle (in units of 1/64 degrees)

Returns: Fixed-point sine result. Signed 16-bit; divide by 32768 to get the actual value.

void gslc_UnionRect	(	gslc_tsRect *	pRect,
		gslc_tsRect	rAddRect
	)

Expand a rect to include another rect.

This routine can be useful to modify an invalidation region to include another modified element

Parameters

[in]	pRect	Initial rect region
[in]	rAddRect	Rectangle to add to the rect region

Returns: none

Functions

Detailed Description

Function Documentation