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|
//*****************************************************************************
//
// circle.c - Routines for drawing circles.
//
// Copyright (c) 2007-2014 Texas Instruments Incorporated. All rights reserved.
// Software License Agreement
//
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
//
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
//
// This is part of revision 2.1.0.12573 of the Tiva Graphics Library.
//
//*****************************************************************************
#include <stdint.h>
#include <stdbool.h>
#include "driverlib/debug.h"
#include "grlib/grlib.h"
//*****************************************************************************
//
//! \addtogroup primitives_api
//! @{
//
//*****************************************************************************
//*****************************************************************************
//
//! Draws a circle.
//!
//! \param pContext is a pointer to the drawing context to use.
//! \param i32X is the X coordinate of the center of the circle.
//! \param i32Y is the Y coordinate of the center of the circle.
//! \param i32Radius is the radius of the circle.
//!
//! This function draws a circle, utilizing the Bresenham circle drawing
//! algorithm. The extent of the circle is from \e i32X - \e i32Radius to
//! \e i32X + \e i32Radius and \e i32Y - \e i32Radius to \e i32Y +
//! \e i32Radius, inclusive.
//!
//! \return None.
//
//*****************************************************************************
void
GrCircleDraw(const tContext *pContext, int32_t i32X, int32_t i32Y,
int32_t i32Radius)
{
int_fast32_t i32A, i32B, i32D, i32X1, i32Y1;
//
// Check the arguments.
//
ASSERT(pContext);
//
// Initialize the variables that control the Bresenham circle drawing
// algorithm.
//
i32A = 0;
i32B = i32Radius;
i32D = 3 - (2 * i32Radius);
//
// Loop until the A delta is greater than the B delta, meaning that the
// entire circle has been drawn.
//
while(i32A <= i32B)
{
//
// Determine the row when subtracting the A delta.
//
i32Y1 = i32Y - i32A;
//
// See if this row is within the clipping region.
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax))
{
//
// Determine the column when subtracting the B delta.
//
i32X1 = i32X - i32B;
//
// If this column is within the clipping region, then draw a pixel
// at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
//
// Determine the column when adding the B delta.
//
i32X1 = i32X + i32B;
//
// If this column is within the clipping region, then draw a pixel
// at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
}
//
// Determine the row when adding the A delta.
//
i32Y1 = i32Y + i32A;
//
// See if this row is within the clipping region, and the A delta is
// not zero (otherwise, it will be the same row as when the A delta was
// subtracted).
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax) &&
(i32A != 0))
{
//
// Determine the column when subtracting the B delta.
//
i32X1 = i32X - i32B;
//
// If this column is within the clipping region, then draw a pixel
// at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
//
// Determine the column when adding the B delta.
//
i32X1 = i32X + i32B;
//
// If this column is within the clipping region, then draw a pixel
// at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
}
//
// Only draw the complementary pixels if the A and B deltas are
// different (otherwise, they describe the same set of pixels).
//
if(i32A != i32B)
{
//
// Determine the row when subtracting the B delta.
//
i32Y1 = i32Y - i32B;
//
// See if this row is within the clipping region.
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax))
{
//
// Determine the column when subtracting the a delta.
//
i32X1 = i32X - i32A;
//
// If this column is within the clipping region, then draw a
// pixel at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
//
// Only draw the mirrored pixel if the A delta is non-zero
// (otherwise, it will be the same pixel).
//
if(i32A != 0)
{
//
// Determine the column when adding the A delta.
//
i32X1 = i32X + i32A;
//
// If this column is within the clipping region, then draw
// a pixel at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
}
}
//
// Determine the row when adding the B delta.
//
i32Y1 = i32Y + i32B;
//
// See if this row is within the clipping region.
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax))
{
//
// Determine the column when subtracting the A delta.
//
i32X1 = i32X - i32A;
//
// If this column is within the clipping region, then draw a
// pixel at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
//
// Only draw the mirrored pixel if the A delta is non-zero
// (otherwise, it will be the same pixel).
//
if(i32A != 0)
{
//
// Determine the column when adding the A delta.
//
i32X1 = i32X + i32A;
//
// If this column is within the clipping region, then draw
// a pixel at that position.
//
if((i32X1 >= pContext->sClipRegion.i16XMin) &&
(i32X1 <= pContext->sClipRegion.i16XMax))
{
GrPixelDraw(pContext, i32X1, i32Y1);
}
}
}
}
//
// See if the error term is negative.
//
if(i32D < 0)
{
//
// Since the error term is negative, adjust it based on a move in
// only the A delta.
//
i32D += (4 * i32A) + 6;
}
else
{
//
// Since the error term is non-negative, adjust it based on a move
// in both the A and B deltas.
//
i32D += (4 * (i32A - i32B)) + 10;
//
// Decrement the B delta.
//
i32B -= 1;
}
//
// Increment the A delta.
//
i32A++;
}
}
//*****************************************************************************
//
//! Draws a filled circle.
//!
//! \param pContext is a pointer to the drawing context to use.
//! \param i32X is the X coordinate of the center of the circle.
//! \param i32Y is the Y coordinate of the center of the circle.
//! \param i32Radius is the radius of the circle.
//!
//! This function draws a filled circle, utilizing the Bresenham circle drawing
//! algorithm. The extent of the circle is from \e i32X - \e i32Radius to
//! \e i32X + \e i32Radius and \e i32Y - \e i32Radius to \e i32Y +
//! \e i32Radius, inclusive.
//!
//! \return None.
//
//*****************************************************************************
void
GrCircleFill(const tContext *pContext, int32_t i32X, int32_t i32Y,
int32_t i32Radius)
{
int_fast32_t i32A, i32B, i32D, i32X1, i32X2, i32Y1;
//
// Check the arguments.
//
ASSERT(pContext);
//
// Initialize the variables that control the Bresenham circle drawing
// algorithm.
//
i32A = 0;
i32B = i32Radius;
i32D = 3 - (2 * i32Radius);
//
// Loop until the A delta is greater than the B delta, meaning that the
// entire circle has been filled.
//
while(i32A <= i32B)
{
//
// Determine the row when subtracting the A delta.
//
i32Y1 = i32Y - i32A;
//
// See if this row is within the clipping region.
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax))
{
//
// Determine the column when subtracting the B delta, and move it
// to the left edge of the clipping region if it is to the left of
// the clipping region.
//
i32X1 = i32X - i32B;
if(i32X1 < pContext->sClipRegion.i16XMin)
{
i32X1 = pContext->sClipRegion.i16XMin;
}
//
// Determine the column when adding the B delta, and move it to the
// right edge of the clipping region if it is to the right of the
// clipping region.
//
i32X2 = i32X + i32B;
if(i32X2 > pContext->sClipRegion.i16XMax)
{
i32X2 = pContext->sClipRegion.i16XMax;
}
//
// Draw a horizontal line if this portion of the circle is within
// the clipping region.
//
if(i32X1 <= i32X2)
{
GrLineDrawH(pContext, i32X1, i32X2, i32Y1);
}
}
//
// Determine the row when adding the A delta.
//
i32Y1 = i32Y + i32A;
//
// See if this row is within the clipping region, and the A delta is
// not zero (otherwise, this describes the same row of the circle).
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax) &&
(i32A != 0))
{
//
// Determine the column when subtracting the B delta, and move it
// to the left edge of the clipping region if it is to the left of
// the clipping region.
//
i32X1 = i32X - i32B;
if(i32X1 < pContext->sClipRegion.i16XMin)
{
i32X1 = pContext->sClipRegion.i16XMin;
}
//
// Determine the column when adding the B delta, and move it to the
// right edge of the clipping region if it is to the right of the
// clipping region.
//
i32X2 = i32X + i32B;
if(i32X2 > pContext->sClipRegion.i16XMax)
{
i32X2 = pContext->sClipRegion.i16XMax;
}
//
// Draw a horizontal line if this portion of the circle is within
// the clipping region.
//
if(i32X1 <= i32X2)
{
GrLineDrawH(pContext, i32X1, i32X2, i32Y1);
}
}
//
// Only draw the complementary lines if the B delta is about to change
// and the A and B delta are different (otherwise, they describe the
// same set of pixels).
//
if((i32D >= 0) && (i32A != i32B))
{
//
// Determine the row when subtracting the B delta.
//
i32Y1 = i32Y - i32B;
//
// See if this row is within the clipping region.
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax))
{
//
// Determine the column when subtracting the A delta, and move
// it to the left edge of the clipping regino if it is to the
// left of the clipping region.
//
i32X1 = i32X - i32A;
if(i32X1 < pContext->sClipRegion.i16XMin)
{
i32X1 = pContext->sClipRegion.i16XMin;
}
//
// Determine the column when adding the A delta, and move it to
// the right edge of the clipping region if it is to the right
// of the clipping region.
//
i32X2 = i32X + i32A;
if(i32X2 > pContext->sClipRegion.i16XMax)
{
i32X2 = pContext->sClipRegion.i16XMax;
}
//
// Draw a horizontal line if this portion of the circle is
// within the clipping region.
//
if(i32X1 <= i32X2)
{
GrLineDrawH(pContext, i32X1, i32X2, i32Y1);
}
}
//
// Determine the row when adding the B delta.
//
i32Y1 = i32Y + i32B;
//
// See if this row is within the clipping region.
//
if((i32Y1 >= pContext->sClipRegion.i16YMin) &&
(i32Y1 <= pContext->sClipRegion.i16YMax))
{
//
// Determine the column when subtracting the A delta, and move
// it to the left edge of the clipping region if it is to the
// left of the clipping region.
//
i32X1 = i32X - i32A;
if(i32X1 < pContext->sClipRegion.i16XMin)
{
i32X1 = pContext->sClipRegion.i16XMin;
}
//
// Determine the column when adding the A delta, and move it to
// the right edge of the clipping region if it is to the right
// of the clipping region.
//
i32X2 = i32X + i32A;
if(i32X2 > pContext->sClipRegion.i16XMax)
{
i32X2 = pContext->sClipRegion.i16XMax;
}
//
// Draw a horizontal line if this portion of the circle is
// within the clipping region.
//
if(i32X1 <= i32X2)
{
GrLineDrawH(pContext, i32X1, i32X2, i32Y1);
}
}
}
//
// See if the error term is negative.
//
if(i32D < 0)
{
//
// Since the error term is negative, adjust it based on a move in
// only the A delta.
//
i32D += (4 * i32A) + 6;
}
else
{
//
// Since the error term is non-negative, adjust it based on a move
// in both the A and B deltas.
//
i32D += (4 * (i32A - i32B)) + 10;
//
// Decrement the B delta.
//
i32B -= 1;
}
//
// Increment the A delta.
//
i32A++;
}
}
//*****************************************************************************
//
// Close the Doxygen group.
//! @}
//
//*****************************************************************************
|
