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Modify drawSmoothArc to support a separate background color for arc ends #3707

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Modify drawSmoothArc to support a separate background color for arc ends #3707

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bf108fd
Modified drawSmoothArc function to allows specifying a different back…
The-Young-Maker Apr 13, 2025
c077589
Update TFT_eSPI.h
The-Young-Maker Apr 14, 2025
75ce379
Modified drawSmoothArc function to allows specifying a different back…
The-Young-Maker Apr 14, 2025
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21 changes: 15 additions & 6 deletions TFT_eSPI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3969,16 +3969,24 @@ uint16_t TFT_eSPI::drawPixel(int32_t x, int32_t y, uint32_t color, uint8_t alpha
** Function name: drawSmoothArc
** Description: Draw a smooth arc clockwise from 6 o'clock
***************************************************************************************/
void TFT_eSPI::drawSmoothArc(int32_t x, int32_t y, int32_t r, int32_t ir, uint32_t startAngle, uint32_t endAngle, uint32_t fg_color, uint32_t bg_color, bool roundEnds)
void TFT_eSPI::drawSmoothArc(int32_t x, int32_t y, int32_t r, int32_t ir,
uint32_t startAngle, uint32_t endAngle,
uint32_t fg_color, uint32_t bg_color, bool roundEnds,
uint32_t end_bg_color)
// Centre at x,y
// r = arc outer radius, ir = arc inner radius. Inclusive so arc thickness = r - ir + 1
// Angles in range 0-360
// Arc foreground colour anti-aliased with background colour at edges
// anti-aliased roundEnd is optional, default is anti-aliased straight end
// Note: rounded ends extend the arc angle so can overlap, user sketch to manage this.
// Added parameter: end_bg_color - background color for antialiasing the ends
// (defaults to bg_color if not specified)
{
inTransaction = true;

// If end_bg_color is not specified (zero), use the same color as bg_color
if (end_bg_color == 0) end_bg_color = bg_color;

if (endAngle != startAngle && (startAngle != 0 || endAngle != 360))
{
float sx = -sinf(startAngle * deg2rad);
Expand All @@ -3990,33 +3998,34 @@ void TFT_eSPI::drawSmoothArc(int32_t x, int32_t y, int32_t r, int32_t ir, uint32
{ // Round ends
sx = sx * (r + ir)/2.0 + x;
sy = sy * (r + ir)/2.0 + y;
drawSpot(sx, sy, (r - ir)/2.0, fg_color, bg_color);
drawSpot(sx, sy, (r - ir)/2.0, fg_color, end_bg_color); // Use end_bg_color here

ex = ex * (r + ir)/2.0 + x;
ey = ey * (r + ir)/2.0 + y;
drawSpot(ex, ey, (r - ir)/2.0, fg_color, bg_color);
drawSpot(ex, ey, (r - ir)/2.0, fg_color, end_bg_color); // Use end_bg_color here
}
else
{ // Square ends
float asx = sx * ir + x;
float asy = sy * ir + y;
float aex = sx * r + x;
float aey = sy * r + y;
drawWedgeLine(asx, asy, aex, aey, 0.3, 0.3, fg_color, bg_color);
drawWedgeLine(asx, asy, aex, aey, 0.3, 0.3, fg_color, end_bg_color); // Use end_bg_color here

asx = ex * ir + x;
asy = ey * ir + y;
aex = ex * r + x;
aey = ey * r + y;
drawWedgeLine(asx, asy, aex, aey, 0.3, 0.3, fg_color, bg_color);
drawWedgeLine(asx, asy, aex, aey, 0.3, 0.3, fg_color, end_bg_color); // Use end_bg_color here
}

// Draw arc
// Draw arc - using original bg_color for sides
drawArc(x, y, r, ir, startAngle, endAngle, fg_color, bg_color);

}
else // Draw full 360
{
// For a full circle, there are no ends, so just use the regular bg_color
drawArc(x, y, r, ir, 0, 360, fg_color, bg_color);
}

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2 changes: 1 addition & 1 deletion TFT_eSPI.h
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Expand Up @@ -543,7 +543,7 @@ class TFT_eSPI : public Print { friend class TFT_eSprite; // Sprite class has ac
// By default the arc is drawn with square ends unless the "roundEnds" parameter is included and set true
// Angle = 0 is at 6 o'clock position, 90 at 9 o'clock etc. The angles must be in range 0-360 or they will be clipped to these limits
// The start angle may be larger than the end angle. Arcs are always drawn clockwise from the start angle.
void drawSmoothArc(int32_t x, int32_t y, int32_t r, int32_t ir, uint32_t startAngle, uint32_t endAngle, uint32_t fg_color, uint32_t bg_color, bool roundEnds = false);
void drawSmoothArc(int32_t x, int32_t y, int32_t r, int32_t ir, uint32_t startAngle, uint32_t endAngle, uint32_t fg_color, uint32_t bg_color, bool roundEnds = false, uint32_t end_bg_color = 0);

// As per "drawSmoothArc" except the ends of the arc are NOT anti-aliased, this facilitates dynamic arc length changes with
// arc segments and ensures clean segment joints.
Expand Down