Line
Simple CanvasWidget capable of drawing a line from one point to another point. The end points can be moved to new locations and the line width can be set and changed. A 10 pixel long line along the top of the screen with a width on 1 pixel has endpoints in (0, 0.5) and (10, 0.5) and line width 1. The Line class calculates the corners of the shape, which in this case would be (0, 0), (10, 0), (10, 1) and (0, 1) and tells CanvasWidgetRenderer to moveTo() the first coordinate and then lineTo() the next coordinates in order. Finally it tells CWR to render the inside of the shape using the set Painter object.
The Line class caches the four corners of the shape to speed up redrawing. In general, drawing lines involve some extra mathematics for calculating the normal vector of the line and this computation would slow down re-draws if not cached.
Note: All coordinates are internally handled as CWRUtil::Q5 which means that floating point values are rounded down to a fixed number of binary digits, for example:
Line line;
line.setStart(1.1f, 1.1f); // Will use (35/32, 35/32) = (1.09375f, 1.09375f)
int x, y;
line.getStart(&x, &y); // Will return (1, 1)
.
Inherits from: CanvasWidget, Widget, Drawable
Public Types
enum | LINE_ENDING_STYLE { BUTT_CAP_ENDING, ROUND_CAP_ENDING, SQUARE_CAP_ENDING } |
Values that represent line ending styles. | |
Public Functions
virtual bool | drawCanvasWidget(const Rect & invalidatedArea) const |
Draw canvas widget for the given invalidated area. | |
template <typename T > void | getEnd(T & x, T & y) const |
Gets the endpoint coordinates for the line. | |
LINE_ENDING_STYLE | getLineEndingStyle() const |
Gets line ending style. | |
template <typename T > T | getLineWidth() const |
Gets line width. | |
template <typename T > void | getLineWidth(T & width) const |
Gets line width. | |
virtual Rect | getMinimalRect() const |
Gets minimal rectangle containing the shape drawn by this widget. | |
template <typename T > void | getStart(T & x, T & y) const |
Gets the starting point of the line as either integers or floats. | |
virtual void | invalidateContent() const |
Tell the framework that the contents of the Drawable needs to be redrawn. | |
Line() | |
void | setCapPrecision(int precision) |
Sets a precision of the arc at the ends of the Line. | |
void | setEnd(CWRUtil::Q5 xQ5, CWRUtil::Q5 yQ5) |
Sets the endpoint coordinates of the line. | |
template <typename T > void | setEnd(T x, T y) |
Sets the endpoint coordinates of the line. | |
template <typename T > void | setLine(T startX, T startY, T endX, T endY) |
Sets the starting point and ending point of the line. | |
void | setLineEndingStyle(LINE_ENDING_STYLE lineEnding) |
Sets line ending style. | |
void | setLineWidth(CWRUtil::Q5 widthQ5) |
Sets the width for this Line. | |
template <typename T > void | setLineWidth(T width) |
Sets the width for this Line. | |
void | setStart(CWRUtil::Q5 xQ5, CWRUtil::Q5 yQ5) |
Sets the starting point of the line. | |
template <typename T > void | setStart(T x, T y) |
Sets the starting point of the line. | |
void | updateEnd(CWRUtil::Q5 xQ5, CWRUtil::Q5 yQ5) |
Update the endpoint for this Line. | |
template <typename T > void | updateEnd(T x, T y) |
Update the endpoint for this Line. | |
void | updateLengthAndAngle(CWRUtil::Q5 length, CWRUtil::Q5 angle) |
Update the end point for this Line given the new length and angle in degrees. | |
void | updateLineWidth(CWRUtil::Q5 widthQ5) |
Update the width for this Line. | |
template <typename T > void | updateLineWidth(T width) |
Update the width for this Line and invalidates the minimal rectangle surrounding the line on screen. | |
void | updateStart(CWRUtil::Q5 xQ5, CWRUtil::Q5 yQ5) |
Update the start point for this Line. | |
template <typename T > void | updateStart(T x, T y) |
Update the start point for this Line. | |
Additional inherited members
Public Functions inherited from CanvasWidget
CanvasWidget() | |
virtual void | draw(const Rect & invalidatedArea) const |
Draws the given invalidated area. | |
virtual uint8_t | getAlpha() const |
Gets the current alpha value of the widget. | |
virtual AbstractPainter & | getPainter() const |
Gets the current painter for the CanvasWidget. | |
virtual Rect | getSolidRect() const |
Gets the largest solid (non-transparent) rectangle. | |
virtual void | invalidate() const |
Invalidates the area covered by this CanvasWidget. | |
void | resetMaxRenderLines() |
Resets the maximum render lines. | |
virtual void | setAlpha(uint8_t newAlpha) |
Sets the opacity (alpha value). | |
virtual void | setPainter(AbstractPainter & painter) |
Sets a painter for the CanvasWidget. | |
Protected Attributes inherited from CanvasWidget
uint8_t | alpha |
The Alpha for this CanvasWidget. | |
Public Functions inherited from Widget
virtual void | getLastChild(int16_t x, int16_t y, Drawable ** last) |
Since a Widget is only one Drawable, Widget::getLastChild simply yields itself as result, but only if the Widget isVisible and isTouchable. | |
Public Functions inherited from Drawable
void | center() |
Centers the Drawable inside its parent. | |
void | centerX() |
Center the Drawable horizontally inside its parent. | |
void | centerY() |
Center the Drawable vertically inside its parent. | |
virtual void | childGeometryChanged() |
This function can be called on parent nodes to signal that the size or position of one or more of its children has changed. | |
virtual void | draw(const Rect & invalidatedArea) const =0 |
Draw this drawable. | |
Drawable() | |
Initializes a new instance of the Drawable class. | |
void | drawToDynamicBitmap(BitmapId id) |
Render the Drawable object into a dynamic bitmap. | |
void | expand(int margin =0) |
Expands the Drawable to have the same size as its parent with a given margin around the edge. | |
Rect | getAbsoluteRect() const |
Helper function for obtaining the rectangle this Drawable covers, expressed in absolute coordinates. | |
virtual Drawable * | getFirstChild() |
Function for obtaining the first child of this drawable if any. | |
int16_t | getHeight() const |
Gets the height of this Drawable. | |
virtual void | getLastChild(int16_t x, int16_t y, Drawable ** last) =0 |
Function for obtaining the the last child of this drawable that intersects with the specified point. | |
Drawable * | getNextSibling() |
Gets the next sibling node. | |
Drawable * | getParent() const |
Returns the parent node. | |
const Rect & | getRect() const |
Gets the rectangle this Drawable covers, in coordinates relative to its parent. | |
virtual Rect | getSolidRect() const =0 |
Get (the largest possible) rectangle that is guaranteed to be solid (opaque). | |
virtual Rect | getSolidRectAbsolute() |
Helper function for obtaining the largest solid rect (as implemented by getSolidRect()) expressed in absolute coordinates. | |
virtual void | getVisibleRect(Rect & rect) const |
Function for finding the visible part of this drawable. | |
int16_t | getWidth() const |
Gets the width of this Drawable. | |
int16_t | getX() const |
Gets the x coordinate of this Drawable, relative to its parent. | |
int16_t | getY() const |
Gets the y coordinate of this Drawable, relative to its parent. | |
virtual void | handleClickEvent(const ClickEvent & event) |
Defines the event handler interface for ClickEvents. | |
virtual void | handleDragEvent(const DragEvent & event) |
Defines the event handler interface for DragEvents. | |
virtual void | handleGestureEvent(const GestureEvent & event) |
Defines the event handler interface for GestureEvents. | |
virtual void | handleTickEvent() |
Called periodically by the framework if the Drawable instance has subscribed to timer ticks. | |
virtual void | invalidate() const |
Tell the framework that this entire Drawable needs to be redrawn. | |
virtual void | invalidateRect(Rect & invalidatedArea) const |
Request that a region of this drawable is redrawn. | |
bool | isTouchable() const |
Gets whether this Drawable receives touch events or not. | |
bool | isVisible() const |
Gets whether this Drawable is visible. | |
virtual void | moveRelative(int16_t x, int16_t y) |
Moves the drawable. | |
virtual void | moveTo(int16_t x, int16_t y) |
Moves the drawable. | |
virtual void | setHeight(int16_t height) |
Sets the height of this drawable. | |
void | setPosition(const Drawable & drawable) |
Sets the position of the Drawable to the same as the given Drawable. | |
void | setPosition(int16_t x, int16_t y, int16_t width, int16_t height) |
Sets the size and position of this Drawable, relative to its parent. | |
void | setTouchable(bool touch) |
Controls whether this Drawable receives touch events or not. | |
void | setVisible(bool vis) |
Controls whether this Drawable should be visible. | |
virtual void | setWidth(int16_t width) |
Sets the width of this drawable. | |
void | setWidthHeight(const Bitmap & bitmap) |
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
void | setWidthHeight(const Drawable & drawable) |
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
void | setWidthHeight(const Rect & rect) |
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
void | setWidthHeight(int16_t width, int16_t height) |
Sets the dimensions (width and height) of the Drawable without changing the x and y coordinates). | |
virtual void | setX(int16_t x) |
Sets the x coordinate of this Drawable, relative to its parent. | |
void | setXY(const Drawable & drawable) |
Sets the x and y coordinates of this Drawable. | |
void | setXY(int16_t x, int16_t y) |
Sets the x and y coordinates of this Drawable, relative to its parent. | |
virtual void | setY(int16_t y) |
Sets the y coordinate of this Drawable, relative to its parent. | |
virtual void | translateRectToAbsolute(Rect & r) const |
Helper function for converting a region of this Drawable to absolute coordinates. | |
virtual | ~Drawable() |
Finalizes an instance of the Drawable class. | |
Protected Attributes inherited from Drawable
Drawable * | nextSibling |
Pointer to the next Drawable. | |
Drawable * | parent |
Pointer to this drawable's parent. | |
Rect | rect |
The coordinates of this Drawable, relative to its parent. | |
bool | touchable |
True if this drawable should receive touch events. | |
bool | visible |
True if this drawable should be drawn. | |
Public Types Documentation
LINE_ENDING_STYLE
enum LINE_ENDING_STYLE
Values that represent line ending styles.
BUTT_CAP_ENDING | The line ending is cut 90 degrees at the end of the line. |
ROUND_CAP_ENDING | The line ending is rounded as a circle with center at the end of the line. |
SQUARE_CAP_ENDING | The line ending is cut 90 degrees, but extends half the width of the line. |
Public Functions Documentation
drawCanvasWidget
virtual bool drawCanvasWidget | ( | const Rect & | invalidatedArea | ) | |
Draw canvas widget for the given invalidated area.
Similar to draw(), but might be invoked several times with increasingly smaller areas to due to memory constraints from the underlying CanvasWidgetRenderer.
invalidatedArea | The invalidated area. |
true if the widget was drawn properly, false if not.
Reimplements: touchgfx::CanvasWidget::drawCanvasWidget
getEnd
void getEnd | ( | T & | x , | const | |
T & | y | const | |||
) | const |
getLineEndingStyle
LINE_ENDING_STYLE getLineEndingStyle | ( | ) | const |
Gets line ending style.
The line ending style.
getLineWidth
T getLineWidth | ( | ) | const |
Gets line width.
T | Generic type parameter, either int or float. |
The line width rounded down to the precision of T.
getLineWidth
void getLineWidth | ( | T & | width | ) | |
Gets line width.
T | Generic type parameter, either int or float. |
width | The line width rounded down to the precision of T. |
getMinimalRect
virtual Rect getMinimalRect | ( | ) | const |
Gets minimal rectangle containing the shape drawn by this widget.
Default implementation returns the size of the entire widget, but this function should be overwritten in subclasses and return the minimal rectangle containing the shape. See classes such as Circle for example implementations.
The minimal rectangle containing the shape drawn.
Reimplements: touchgfx::CanvasWidget::getMinimalRect
getStart
void getStart | ( | T & | x , | const | |
T & | y | const | |||
) | const |
invalidateContent
virtual void invalidateContent | ( | ) | const |
Tell the framework that the contents of the Drawable needs to be redrawn.
If the Drawable is invisible, nothing happens. Subclasses of Drawable are encouraged to implement this function and invalidate as little as possible, i.e. the smallest rectangle covering the visual element(s) drawn by the widget.
Reimplements: touchgfx::Drawable::invalidateContent
Line
Line | ( | ) |
setCapPrecision
void setCapPrecision | ( | int | precision | ) | |
Sets a precision of the arc at the ends of the Line.
This only works for ROUND_CAP_ENDING. The precision is given in degrees where 18 is the default which results in a nice half circle with 10 line segments. 90 will draw "an arrow head", 180 will look exactly like a BUTT_CAP_ENDING.
precision | The new ROUND_CAP_ENDING precision. |
Note
The line is not invalidated. This is only used if line ending is set to ROUND_CAP_ENDING.
setEnd
void setEnd | ( | CWRUtil::Q5 | xQ5 , | ||
CWRUtil::Q5 | yQ5 | ||||
) |
setEnd
void setEnd | ( | T | x , | ||
T | y | ||||
) |
setLine
void setLine | ( | T | startX , | ||
T | startY , | ||||
T | endX , | ||||
T | endY | ||||
) |
Sets the starting point and ending point of the line.
T | Generic type parameter, either int or float. |
startX | The x coordinate of the start point. |
startY | The y coordinate of the start point. |
endX | The x coordinate of the end point. |
endY | The y coordinate of the end point. |
Note
The area containing the Line is not invalidated.
setLineEndingStyle
void setLineEndingStyle | ( | LINE_ENDING_STYLE | lineEnding | ) | |
Sets line ending style.
The same style is applied to both ends of the line.
lineEnding | The line ending style. |
Note
The area containing the Line is not invalidated.
setLineWidth
void setLineWidth | ( | CWRUtil::Q5 | widthQ5 | ) | |
setLineWidth
void setLineWidth | ( | T | width | ) | |
setStart
void setStart | ( | CWRUtil::Q5 | xQ5 , | ||
CWRUtil::Q5 | yQ5 | ||||
) |
Sets the starting point of the line.
xQ5 | The x coordinate of the start point in Q5 format. |
yQ5 | The y coordinate of the start point in Q5 format. |
Note
The area containing the Line is not invalidated.
setStart
void setStart | ( | T | x , | ||
T | y | ||||
) |
Sets the starting point of the line.
T | Generic type parameter, either int or float. |
x | The x coordinate of the start point. |
y | The y coordinate of the start point. |
Note
The area containing the Line is not invalidated.
updateEnd
void updateEnd | ( | CWRUtil::Q5 | xQ5 , | ||
CWRUtil::Q5 | yQ5 | ||||
) |
Update the endpoint for this Line.
The rectangle that surrounds the line before and after will be invalidated.
xQ5 | The x coordinate of the end point in Q5 format. |
yQ5 | The y coordinate of the end point in Q5 format. |
Note
The area containing the Line is invalidated before and after the change.
updateEnd
void updateEnd | ( | T | x , | ||
T | y | ||||
) |
Update the endpoint for this Line.
The rectangle that surrounds the line before and after will be invalidated.
T | Generic type parameter, either int or float. |
x | The x coordinate of the end point. |
y | The y coordinate of the end point. |
Note
The area containing the Line is invalidated before and after the change.
updateLengthAndAngle
void updateLengthAndAngle | ( | CWRUtil::Q5 | length , | ||
CWRUtil::Q5 | angle | ||||
) |
Update the end point for this Line given the new length and angle in degrees.
The rectangle that surrounds the line before and after will be invalidated. The starting coordinates will be fixed but the ending point will be updated. This is simply a different way to update the ending point.
length | The new length of the line in Q5 format. |
angle | The new angle of the line in Q5 format. |
Note
The area containing the Line is invalidated before and after the change. Angles are given in degrees, so a full circle is 360.
updateLineWidth
void updateLineWidth | ( | CWRUtil::Q5 | widthQ5 | ) | |
updateLineWidth
void updateLineWidth | ( | T | width | ) | |
Update the width for this Line and invalidates the minimal rectangle surrounding the line on screen.
T | Generic type parameter, either int or float. |
width | The width of the line measured in pixels. |
Note
The area containing the Line is invalidated before and after the change.
updateStart
void updateStart | ( | CWRUtil::Q5 | xQ5 , | ||
CWRUtil::Q5 | yQ5 | ||||
) |
Update the start point for this Line.
The rectangle that surrounds the line before and after will be invalidated.
xQ5 | The x coordinate of the start point in CWRUtil::Q5 format. |
yQ5 | The y coordinate of the start point in CWRUtil::Q5 format. |
Note
The area containing the Line is invalidated before and after the change.
updateStart
void updateStart | ( | T | x , | ||
T | y | ||||
) |
Update the start point for this Line.
The rectangle that surrounds the line before and after will be invalidated.
T | Generic type parameter, either int or float. |
x | The x coordinate of the start point. |
y | The y coordinate of the start point. |
Note
The area containing the Line is invalidated before and after the change.