QRCode
touchgfx/widgets/QRCode.hpp
Widget capable of generating and showing a QRCode. This widget uses the QR Code generator library (C). https://www.nayuki.io/page/qr-code-generator-library
Important: The application must allocate buffers and provide these through QRCode::setBuffers.
The QRCode supports framebuffer formats RGB565, RGB888, ARGB8888.
Inherits from: Widget, Drawable
Public Types
enum | ECCLevel { ECC_LOW = 0, ECC_MED = 1, ECC_QUARTILE = 2, ECC_HIGH = 3 } |
ECC levels. | |
Public Functions
bool | convertBinaryDataToQRCode(const uint8_t * data, size_t length) |
Convert data to QRCode data and save in the buffer. | |
bool | convertStringToQRCode(const char * text) |
Convert a text to QRCode data and save in the buffer. | |
virtual void | draw(const Rect & invalidatedArea) const |
Draw this drawable. | |
uint8_t | getAlpha() const |
Gets the current alpha value of the widget. | |
ECCLevel | getErrorCorrectionLevel() const |
Gets the current error correction level. | |
uint8_t | getQRCodeVersion() const |
Gets the current QRCode version. | |
int | getScale() const |
Gets the current scale of the QRCode. | |
virtual Rect | getSolidRect() const |
Get (the largest possible) rectangle that is guaranteed to be solid (opaque). | |
QRCode() | |
Construct a new QRCode using black and white colors with alpha 255. | |
void | setAlpha(uint8_t newAlpha) |
Sets the opacity (alpha value). | |
void | setBuffers(uint8_t qrBuffer, uint8_t tempBuffer) |
Sets the buffers used for QRCode generation. | |
void | setColors(colortype colorBlack, colortype colorWhite) |
Sets the colors used for the QRCode. | |
void | setErrorCorrectionLevel(ECCLevel level) |
Sets the desired level of error correction codes. | |
void | setQRCodeVersion(uint8_t version) |
Sets the version (size) of the QRCode. | |
void | setScale(int newScale) |
Sets the scale of the QRCode. | |
Additional inherited members
Public Functions inherited from Widget
virtual void | getLastChild(int16_t , int16_t , 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. | |
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 | 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 | invalidateContent() const |
Tell the framework that the contents of the 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 & other) |
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
ECCLevel
enum ECCLevel
ECC levels.
ECC_LOW | Low level of ECC (handles around 7% faults) |
ECC_MED | Medium level of ECC (handles around 15% faults) |
ECC_QUARTILE | Good level of ECC (handles around 25% faults) |
ECC_HIGH | High level of ECC (handles around 30% faults) |
Public Functions Documentation
convertBinaryDataToQRCode
bool convertBinaryDataToQRCode | ( | const uint8_t * | data , | ||
size_t | length | ||||
) |
Convert data to QRCode data and save in the buffer.
The function returns false if the encoding of the data does not fit in the QRCode. This depends on the version of the QRCode and the ECCLevel. If the data was not accepted, the QRCodeWidget does not draw anything. User must call invalidate() after changing the data. This function can e.g. be used to store UTF8 encoded strings.
data | The data to show in the QRCode. |
length | Length of the data. |
True if data was converted.
convertStringToQRCode
bool convertStringToQRCode | ( | const char * | text | ) | |
Convert a text to QRCode data and save in the buffer.
The function returns false if the encoding of the string does not fit in the QRCode. This depends on the version of the QRCode and the ECCLevel. If the text was not accepted, the QRCodeWidget does not draw anything. User must call invalidate() after changing the data.
text | The text to show in the QRCode. |
True if data was converted.
draw
Draw this drawable.
It is a requirement that the draw implementation does not draw outside the region specified by invalidatedArea.
invalidatedArea | The sub-region of this drawable that needs to be redrawn, expressed in coordinates relative to its parent (e.g. for a complete redraw, invalidatedArea will be (0, 0, width, height). |
Reimplements: touchgfx::Drawable::draw
getAlpha
uint8_t getAlpha | ( | ) | const |
Gets the current alpha value of the widget.
The alpha value is in range 255 (solid) to 0 (invisible).
The current alpha value.
getErrorCorrectionLevel
ECCLevel getErrorCorrectionLevel | ( | ) | const |
Gets the current error correction level.
The current error correction level.
getQRCodeVersion
uint8_t getQRCodeVersion | ( | ) | const |
getScale
int getScale | ( | ) | const |
getSolidRect
virtual Rect getSolidRect | ( | ) | const |
Get (the largest possible) rectangle that is guaranteed to be solid (opaque).
This information is important, as any Drawable underneath the solid area does not need to be drawn.
The solid rectangle part of the Drawable.
Note
The rectangle returned must be relative to upper left corner of the Drawable, meaning that a completely solid widget should return the full size Rect(0, 0, getWidth(), getHeight()). If no area can be guaranteed to be solid, an empty Rect must be returned. Failing to return the correct rectangle may result in errors on the display.
Reimplements: touchgfx::Drawable::getSolidRect
QRCode
QRCode | ( | ) |
Construct a new QRCode using black and white colors with alpha 255.
The user must supply buffers and set the scale and QR version as wanted.
setAlpha
void setAlpha | ( | uint8_t | newAlpha | ) | |
Sets the opacity (alpha value).
This can be used to fade it away by gradually decreasing the alpha value from 255 (solid) to 0 (invisible).
newAlpha | The new alpha value. 255=solid, 0=invisible. |
Note
The user code must call invalidate() in order to update the display.
setBuffers
void setBuffers | ( | uint8_t * | qrBuffer , | ||
uint8_t * | tempBuffer | ||||
) |
Sets the buffers used for QRCode generation.
The length of the buffers must match the version of the QRCode used. Use the above macro QRCODE_BUFFER_SIZE(version) when allocating buffers. The qrBuffer is holding the QRCode bit-stream. The tempBuffer is only used during QRCode generation. It can be used for other purposes afterwards and shared between Widgets.
qrBuffer | Buffer to store the QRcode. |
tempBuffer | Scratch buffer used during QRCode generation. |
setColors
Sets the colors used for the QRCode.
Black and White is traditionally used, but other colors will also work.
colorBlack | The color used for 'black' pixels. |
colorWhite | The color used the 'white' pixels. |
setErrorCorrectionLevel
void setErrorCorrectionLevel | ( | ECCLevel | level | ) | |
Sets the desired level of error correction codes.
level | The level of ECC. |
setQRCodeVersion
void setQRCodeVersion | ( | uint8_t | version | ) | |