# qtmypaint

**Repository Path**: mirrors_fabioz/qtmypaint

## Basic Information

- **Project Name**: qtmypaint
- **Description**: libmypaint integration for QT based applications
- **Primary Language**: Unknown
- **License**: BSD-3-Clause
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-24
- **Last Updated**: 2025-09-13

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# qtmypaint

qtmypaint is an interface to help integrate the libmypaint brush engine library within your QT based applications. (The example's GUI is based on a demo application made by Sebastien Leon)

The main code of this interface is stored in the sub-folder "src"

Please feel free to fork and modify this project.

License: Modified BSD License, see [LICENSE](./LICENSE) for details


Prerequisites
---------------

Build dependencies:
* [json-c](https://github.com/json-c/json-c/wiki) A copy of json-c is included in this project
* [libmypaint](https://github.com/mypaint/libmypaint) A copy of libmypaint is included in this project. It has been modified to be built in a C++ environment. It may not be the best approach. "libmypaint.c" has to be included so we can't use the headers of a pre-built version of the C lib.


Compile
-------

    cd qtmypaint
    qmake
    make

On Linux, you can then run the demo with

    ./demo/demo

_Note that on Mac and Windows, the path to the demo binary may be different._


Usage
---------

A global object is used for the communication with libmypaint


    MPHandler *mypaint = MPHandler::handler();


### Set the size of your drawing surface :

    QSize size = ...;
    mypaint->setSurfaceSize(size);


### Load a brush from json data :

    QByteArray jsonData = ...;
    mypaint->loadBrush(jsonData);


### Set a brush color :

    QColor color = ...;
    mypaint->setBrushColor(color);

_Note that the alpha value is not handled by this method as the opacity of the stroke is part of the brush settings._
_If you wish to force the color opacity, you should use MPHandler::setBrushValue() with MYPAINT_BRUSH_SETTING_OPAQUE._

### Get and set a brush specific setting value :

    float value = ...;
    mypaint->setBrushValue(MYPAINT_BRUSH_SETTING_RADIUS_LOGARITHMIC, value);

    value = mypaint->getBrushValue(MYPAINT_BRUSH_SETTING_RADIUS_LOGARITHMIC)

_Note that the setting type is defined by libmypaint's MyPaintBrushSetting enum._


### Draw a stroke :

    // Call this once on press event
    mypaint->startStroke();

    // Call this on each move event
    mypaint->strokeTo(x, y); // Basic call
    mypaint->strokeTo(x, y, pressure, xTilt,  yTilt); // Call with tablet handling

A signal/slot mecanism is used to handle stroke events :

* newTile(MPSurface*, MPTile*) is called when a tile is added to the surface (the brush is drawing on a blank area)
* updateTile(MPSurface*, MPTile*) is called when a tile is visually updated.

MPTile inherits from QGraphicsItem and should be added to a QGraphicsScene object on the newTile() event.


### Render the surface as an image :

    QImage image = mypaint->renderImage();


### Clear the surface :

    mypaint->clearSurface();

* clearedSurface(MPSurface*) is called when the surface has been cleared.

_Note that in order to optimize the output of the final UI, when a surface is cleared, all the MPtiles (QGraphicsItem) that represent this surface are automatically removed from their QGraphicsScene._
_You don't need to worry about that._


### Load the surface with an existing image :

    QImage image = ...;
    mypaint->loadImage(image);