### Build and Install libdxfrw

Source: https://github.com/librecad/libdxfrw/blob/master/README.md

Standard build process for the library using CMake and make.

```bash
mkdir build
cd build
cmake ..
make 
sudo make install
```

```bash
mkdir release
cd release
cmake -DCMAKE_BUILD_TYPE=Release ..
make 
sudo make install
```

```bash
mkdir release
cd release
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX:PATH=/usr .. && make all
make 
sudo make install
```

--------------------------------

### Initialize Converter Main Function

Source: https://context7.com/librecad/libdxfrw/llms.txt

Example main function demonstrating how to invoke the converter with input and output file arguments.

```cpp
int main(int argc, char* argv[]) {
    if (argc < 3) {
        std::cout << "Usage: converter input.dwg output.dxf" << std::endl;
        return 1;
    }

    Converter converter;
    bool success = converter.convert(argv[1], argv[2], DRW::AC1015, false);

    return success ? 0 : 1;
}
```

--------------------------------

### Write DXF File

Source: https://context7.com/librecad/libdxfrw/llms.txt

Example of initializing a writer and saving DXF data to a file.

```cpp
writerInterface.setWriter(&dxf);
    writerInterface.addLinesToExport(lines);
    writerInterface.addCirclesToExport(circles);

    // Write DXF - DRW::AC1015 = AutoCAD 2000, false = ASCII format
    bool success = dxf.write(&writerInterface, DRW::AC1015, false);

    if (!success) {
        std::cerr << "Failed to write DXF file" << std::endl;
        return 1;
    }
    return 0;
}
```

--------------------------------

### Build libdxfrw with CMake

Source: https://context7.com/librecad/libdxfrw/llms.txt

Standard commands for cloning, configuring, and installing the library for debug or release builds.

```bash
# Clone repository
git clone https://github.com/LibreCAD/libdxfrw.git
cd libdxfrw

# Debug build
mkdir build && cd build
cmake ..
make
sudo make install

# Release build
mkdir release && cd release
cmake -DCMAKE_BUILD_TYPE=Release ..
make
sudo make install

# Ubuntu/Debian with /usr prefix
mkdir release && cd release
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX:PATH=/usr ..
make
sudo make install
```

--------------------------------

### DRW_Circle - Circle Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents a circle with a center point and radius. The example shows how to define a circle's properties and write it to a DXF file.

```APIDOC
## DRW_Circle - Circle Entity

### Description
Represents a circle with center point and radius.

### Usage Example
```cpp
DRW_Circle circle;
circle.basePoint = DRW_Coord(50, 50, 0);  // Center point
circle.radious = 25.0;                     // Radius
circle.thickness = 0.0;
circle.layer = "Circles";
circle.color = 3;  // Green

dxfRW dxf("circles.dxf");
dxf.writeCircle(&circle);
```
```

--------------------------------

### DRW_Point - Point Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents a single point in 3D space with optional thickness and extrusion direction. Example shows how to create and write a point to a DXF file.

```APIDOC
## DRW_Point - Point Entity

### Description
Represents a single point in 3D space with optional thickness and extrusion direction.

### Usage Example
```cpp
DRW_Point point;
point.basePoint.x = 100.0;
point.basePoint.y = 50.0;
point.basePoint.z = 0.0;
point.thickness = 0.0;
point.layer = "Points";
point.color = DRW::ColorByLayer;

// Write point
dxfRW dxf("points.dxf");
dxf.writePoint(&point);
```
```

--------------------------------

### DRW_Spline - Spline Curve

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents a NURBS spline curve. The example illustrates setting up control points, knots, degree, and flags before writing the spline to a DXF file.

```APIDOC
## DRW_Spline - Spline Curve

### Description
Represents a NURBS spline curve with control points, knots, and optional fit points.

### Usage Example
```cpp
DRW_Spline spline;
spline.layer = "Splines";
spline.flags = 8;    // Planar spline
spline.degree = 3;   // Cubic spline

// Add control points
spline.controllist.push_back(std::make_shared<DRW_Coord>(0, 0, 0));
spline.controllist.push_back(std::make_shared<DRW_Coord>(50, 100, 0));
spline.controllist.push_back(std::make_shared<DRW_Coord>(100, 100, 0));
spline.controllist.push_back(std::make_shared<DRW_Coord>(150, 0, 0));

spline.ncontrol = spline.controllist.size();

// Add knot values for cubic spline
spline.knotslist = {0, 0, 0, 0, 1, 1, 1, 1};
spline.nknots = spline.knotslist.size();

dxfRW dxf("splines.dxf");
dxf.writeSpline(&spline);
```
```

--------------------------------

### DRW_LWPolyline - Lightweight Polyline

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents a 2D polyline that can include arc segments (bulge) and variable width. The example demonstrates adding vertices and closing the polyline before writing.

```APIDOC
## DRW_LWPolyline - Lightweight Polyline

### Description
Represents a 2D polyline with optional bulge (arc segments) and variable width.

### Usage Example
```cpp
DRW_LWPolyline polyline;
polyline.layer = "Polylines";
polyline.flags = 0;  // 0 = open, 1 = closed
polyline.elevation = 0.0;
polyline.thickness = 0.0;

// Add vertices
DRW_Vertex2D v1(0, 0, 0);      // x, y, bulge
DRW_Vertex2D v2(100, 0, 0);
DRW_Vertex2D v3(100, 100, 0.5); // Bulge creates arc to next vertex
DRW_Vertex2D v4(0, 100, 0);

polyline.addVertex(v1);
polyline.addVertex(v2);
polyline.addVertex(v3);
polyline.addVertex(v4);

// Close the polyline
polyline.flags = 1;

dxfRW dxf("polylines.dxf");
dxf.writeLWPolyline(&polyline);
```
```

--------------------------------

### DRW_Ellipse - Ellipse Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents an ellipse or elliptical arc. The example shows how to define the center, major axis endpoint, ratio, and parameter angles, then write it to a DXF file.

```APIDOC
## DRW_Ellipse - Ellipse Entity

### Description
Represents an ellipse or elliptical arc with center, major axis endpoint, ratio, and parameter angles.

### Usage Example
```cpp
DRW_Ellipse ellipse;
ellipse.basePoint = DRW_Coord(100, 100, 0);  // Center point
ellipse.secPoint = DRW_Coord(50, 0, 0);      // Major axis endpoint (relative)
ellipse.ratio = 0.5;                          // Minor/major axis ratio
ellipse.staparam = 0.0;                       // Start parameter (radians)
ellipse.endparam = 2 * M_PI;                  // End parameter (full ellipse)
ellipse.layer = "Ellipses";

dxfRW dxf("ellipses.dxf");
dxf.writeEllipse(&ellipse);
```
```

--------------------------------

### DRW_Polyline - 3D Polyline

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents a 3D polyline composed of vertex entities, supporting variable width and bulge. The example shows adding 3D vertices and writing the polyline.

```APIDOC
## DRW_Polyline - 3D Polyline

### Description
Represents a 3D polyline with vertex entities supporting variable width and bulge.

### Usage Example
```cpp
DRW_Polyline polyline;
polyline.layer = "3DPolylines";
polyline.flags = 8;  // 8 = 3D polyline

// Add 3D vertices
DRW_Vertex v1(0, 0, 0, 0);       // x, y, z, bulge
DRW_Vertex v2(100, 0, 50, 0);
DRW_Vertex v3(100, 100, 100, 0);
DRW_Vertex v4(0, 100, 50, 0);

polyline.addVertex(v1);
polyline.addVertex(v2);
polyline.addVertex(v3);
polyline.addVertex(v4);

dxfRW dxf("polyline3d.dxf");
dxf.writePolyline(&polyline);
```
```

--------------------------------

### DRW_Line - Line Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents a line segment defined by two endpoints. The example demonstrates creating a line with specified coordinates, layer, line type, color, and weight, then writing it to a DXF file.

```APIDOC
## DRW_Line - Line Entity

### Description
Represents a line segment defined by two endpoints.

### Usage Example
```cpp
DRW_Line line;
line.basePoint = DRW_Coord(0, 0, 0);      // Start point
line.secPoint = DRW_Coord(100, 200, 0);   // End point
line.layer = "Lines";
line.lineType = "CONTINUOUS";
line.color = 1;  // Red
line.lWeight = DRW_LW_Conv::width06;  // 0.20mm

dxfRW dxf("lines.dxf");
dxf.writeLine(&line);
```
```

--------------------------------

### DRW_Arc - Arc Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Represents a circular arc defined by its center, radius, and start/end angles in radians. The example includes setting these properties and writing the arc to a DXF file.

```APIDOC
## DRW_Arc - Arc Entity

### Description
Represents a circular arc with center, radius, and start/end angles in radians.

### Usage Example
```cpp
#include <cmath>

DRW_Arc arc;
arc.basePoint = DRW_Coord(100, 100, 0);   // Center point
arc.radious = 50.0;                        // Radius
arc.staangle = 0.0;                        // Start angle (radians)
arc.endangle = M_PI / 2;                   // End angle (90 degrees)
arc.isccw = 1;                             // Counter-clockwise
arc.layer = "Arcs";

dxfRW dxf("arcs.dxf");
dxf.writeArc(&arc);
```
```

--------------------------------

### Prepare and Write DXF Data

Source: https://context7.com/librecad/libdxfrw/llms.txt

This snippet demonstrates preparing line and circle data, creating a dxfRW object for file output, and initializing the custom writer interface.

```cpp
int main() {
    // Prepare data
    std::vector<DRW_Line> lines;
    DRW_Line line;
    line.basePoint = DRW_Coord(0, 0, 0);
    line.secPoint = DRW_Coord(100, 100, 0);
    line.layer = "MyLayer";
    lines.push_back(line);

    std::vector<DRW_Circle> circles;
    DRW_Circle circle;
    circle.basePoint = DRW_Coord(50, 50, 0);
    circle.radious = 25;
    circle.layer = "0";
    circles.push_back(circle);

    // Create writer
    dxfRW dxf("output.dxf");
    DxfWriter writerInterface;

```

--------------------------------

### Read a DWG file with dwgR

Source: https://context7.com/librecad/libdxfrw/llms.txt

Demonstrates reading a DWG file using the dwgR class and the DRW_Interface callback system.

```cpp
#include "libdwgr.h"
#include "drw_interface.h"

// Reading a DWG file
class MyInterface : public DRW_Interface {
    // Implement callback methods
};

int main() {
    const char* filename = "drawing.dwg";
    dwgR dwg(filename);

    dwg.setDebug(DRW::DebugLevel::Debug);

    MyInterface interface;
    bool success = dwg.read(&interface, false);

    if (!success) {
        DRW::Version version = dwg.getVersion();
        DRW::error err = dwg.getError();
        std::cerr << "DWG read error: " << err << std::endl;
        return 1;
    }

    std::cout << "Successfully read DWG version: " << version << std::endl;
    return 0;
}
```

--------------------------------

### Read a DXF file with dxfRW

Source: https://context7.com/librecad/libdxfrw/llms.txt

Demonstrates reading a DXF file by implementing the DRW_Interface and using the dxfRW class.

```cpp
#include "libdxfrw.h"
#include "drw_interface.h"

// Reading a DXF file
class MyInterface : public DRW_Interface {
    // Implement callback methods (see DRW_Interface section)
};

int main() {
    const char* filename = "drawing.dxf";
    dxfRW dxf(filename);

    // Enable debug output for troubleshooting
    dxf.setDebug(DRW::DebugLevel::Debug);

    MyInterface interface;
    // Read file: second parameter enables extrusion conversion to 2D
    bool success = dxf.read(&interface, false);

    if (!success) {
        DRW::Version version = dxf.getVersion();
        DRW::error err = dxf.getError();
        std::cerr << "Read error: " << err << " (version: " << version << ")" << std::endl;
        return 1;
    }
    return 0;
}
```

--------------------------------

### Write Hatch Pattern to DXF

Source: https://context7.com/librecad/libdxfrw/llms.txt

Use DRW_Hatch to create a filled area with a pattern or solid fill. Define boundary loops using lines or other entities.

```cpp
DRW_Hatch hatch;
hatch.name = "ANSI31";           // Pattern name
hatch.solid = 0;                 // 0 = pattern, 1 = solid
hatch.scale = 1.0;
hatch.angle = 0.0;
hatch.layer = "Hatches";

// Create boundary loop
auto loop = std::make_shared<DRW_HatchLoop>(0);

// Add boundary lines (rectangle)
auto line1 = std::make_shared<DRW_Line>();
line1->basePoint = DRW_Coord(0, 0, 0);
line1->secPoint = DRW_Coord(100, 0, 0);
loop->objlist.push_back(line1);

auto line2 = std::make_shared<DRW_Line>();
line2->basePoint = DRW_Coord(100, 0, 0);
line2->secPoint = DRW_Coord(100, 100, 0);
loop->objlist.push_back(line2);

auto line3 = std::make_shared<DRW_Line>();
line3->basePoint = DRW_Coord(100, 100, 0);
line3->secPoint = DRW_Coord(0, 100, 0);
loop->objlist.push_back(line3);

auto line4 = std::make_shared<DRW_Line>();
line4->basePoint = DRW_Coord(0, 100, 0);
line4->secPoint = DRW_Coord(0, 0, 0);
loop->objlist.push_back(line4);

loop->update();
hatch.appendLoop(loop);
hatch.loopsnum = 1;

dxfRW dxf("hatches.dxf");
dxf.writeHatch(&hatch);
```

--------------------------------

### DXF Version Constants

Source: https://context7.com/librecad/libdxfrw/llms.txt

Lists supported AutoCAD versions for reading and writing via the DRW::Version enum.

```APIDOC
## DXF Version Constants

### Description
The DRW::Version enum defines supported AutoCAD versions for reading and writing.

### Supported Versions
- DRW::UNKNOWNV
- DRW::AC1009 (R11/R12)
- DRW::AC1012 (R13)
- DRW::AC1014 (R14)
- DRW::AC1015 (2000/2002)
- DRW::AC1018 (2004/2005/2006)
- DRW::AC1021 (2007/2008/2009)
- DRW::AC1024 (2010/2011/2012)
- DRW::AC1027 (2013-2017)
- DRW::AC1032 (2018-2020)

### Request Example
```cpp
dxfRW dxf("output.dxf");
dxf.write(&interface, DRW::AC1015, false); // ASCII
dxf.write(&interface, DRW::AC1015, true);  // Binary
```
```

--------------------------------

### Create DRW_Point Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Defines a point in 3D space and writes it to a DXF file.

```cpp
DRW_Point point;
point.basePoint.x = 100.0;
point.basePoint.y = 50.0;
point.basePoint.z = 0.0;
point.thickness = 0.0;
point.layer = "Points";
point.color = DRW::ColorByLayer;

// Write point
dxfRW dxf("points.dxf");
dxf.writePoint(&point);
```

--------------------------------

### Create DRW_LWPolyline Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Defines a 2D lightweight polyline with vertices and optional bulge.

```cpp
DRW_LWPolyline polyline;
polyline.layer = "Polylines";
polyline.flags = 0;  // 0 = open, 1 = closed
polyline.elevation = 0.0;
polyline.thickness = 0.0;

// Add vertices
DRW_Vertex2D v1(0, 0, 0);      // x, y, bulge
DRW_Vertex2D v2(100, 0, 0);
DRW_Vertex2D v3(100, 100, 0.5); // Bulge creates arc to next vertex
DRW_Vertex2D v4(0, 100, 0);

polyline.addVertex(v1);
polyline.addVertex(v2);
polyline.addVertex(v3);
polyline.addVertex(v4);

// Close the polyline
polyline.flags = 1;

dxfRW dxf("polylines.dxf");
dxf.writeLWPolyline(&polyline);
```

--------------------------------

### Implement DXF Writer Interface

Source: https://context7.com/librecad/libdxfrw/llms.txt

Implement the DRW_Interface to define callbacks for writing DXF data. This class handles adding header information, layers, line types, and entities to the DXF file.

```cpp
#include "libdxfrw.h"
#include "drw_interface.h"

class DxfWriter : public DRW_Interface {
private:
    dxfRW* writer;
    std::vector<DRW_Line> linesToWrite;
    std::vector<DRW_Circle> circlesToWrite;
    std::vector<DRW_Layer> layersToWrite;

public:
    void addLinesToExport(const std::vector<DRW_Line>& lines) {
        linesToWrite = lines;
    }

    void addCirclesToExport(const std::vector<DRW_Circle>& circles) {
        circlesToWrite = circles;
    }

    void setWriter(dxfRW* w) { writer = w; }

    // Writer callbacks
    void writeHeader(DRW_Header& data) override {
        // Add header variables
        data.addStr("$ACADVER", "AC1015", 1);  // AutoCAD 2000
        data.addCoord("$INSBASE", DRW_Coord(0, 0, 0), 10);
        data.addCoord("$EXTMIN", DRW_Coord(0, 0, 0), 10);
        data.addCoord("$EXTMAX", DRW_Coord(1000, 1000, 0), 10);
    }

    void writeLayers() override {
        // Write default layer
        DRW_Layer layer;
        layer.name = "0";
        layer.color = 7;  // White
        layer.lineType = "CONTINUOUS";
        writer->writeLayer(&layer);

        // Write custom layers
        DRW_Layer customLayer;
        customLayer.name = "MyLayer";
        customLayer.color = 1;  // Red
        customLayer.lineType = "CONTINUOUS";
        writer->writeLayer(&customLayer);
    }

    void writeLTypes() override {
        DRW_LType ltype;
        ltype.name = "CONTINUOUS";
        ltype.desc = "Solid line";
        writer->writeLineType(&ltype);
    }

    void writeEntities() override {
        // Write lines
        for (auto& line : linesToWrite) {
            writer->writeLine(&line);
        }

        // Write circles
        for (auto& circle : circlesToWrite) {
            writer->writeCircle(&circle);
        }
    }

    void writeBlocks() override {}
    void writeBlockRecords() override {}
    void writeTextstyles() override {}
    void writeVports() override {}
    void writeDimstyles() override {}
    void writeObjects() override {}
    void writeAppId() override {}

    // Empty reader callbacks
    void addHeader(const DRW_Header* data) override {}
    void addLType(const DRW_LType& data) override {}
    void addLayer(const DRW_Layer& data) override {}
    void addDimStyle(const DRW_Dimstyle& data) override {}
    void addVport(const DRW_Vport& data) override {}
    void addTextStyle(const DRW_Textstyle& data) override {}
    void addAppId(const DRW_AppId& data) override {}
    void addBlock(const DRW_Block& data) override {}
    void setBlock(const int handle) override {}
    void endBlock() override {}
    void addPoint(const DRW_Point& data) override {}
    void addLine(const DRW_Line& data) override {}
    void addCircle(const DRW_Circle& data) override {}
    void addArc(const DRW_Arc& data) override {}
    void addEllipse(const DRW_Ellipse& data) override {}
    void addRay(const DRW_Ray& data) override {}
    void addXline(const DRW_Xline& data) override {}
    void addLWPolyline(const DRW_LWPolyline& data) override {}
    void addPolyline(const DRW_Polyline& data) override {}
    void addSpline(const DRW_Spline* data) override {}
    void addKnot(const DRW_Entity& data) override {}
    void addInsert(const DRW_Insert& data) override {}
    void addTrace(const DRW_Trace& data) override {}
    void add3dFace(const DRW_3Dface& data) override {}
    void addSolid(const DRW_Solid& data) override {}
    void addMText(const DRW_MText& data) override {}
    void addText(const DRW_Text& data) override {}
    void addDimAlign(const DRW_DimAligned* data) override {}
    void addDimLinear(const DRW_DimLinear* data) override {}
    void addDimRadial(const DRW_DimRadial* data) override {}
    void addDimDiametric(const DRW_DimDiametric* data) override {}
    void addDimAngular(const DRW_DimAngular* data) override {}
    void addDimAngular3P(const DRW_DimAngular3p* data) override {}
    void addDimOrdinate(const DRW_DimOrdinate* data) override {}
    void addLeader(const DRW_Leader* data) override {}
    void addHatch(const DRW_Hatch* data) override {}
    void addViewport(const DRW_Viewport& data) override {}
    void addImage(const DRW_Image* data) override {}
    void linkImage(const DRW_ImageDef* data) override {}
    void addComment(const char* comment) override {}
    void addPlotSettings(const DRW_PlotSettings* data) override {}
};

```

--------------------------------

### Implement DRW_Interface for DXF/DWG parsing

Source: https://context7.com/librecad/libdxfrw/llms.txt

Inherit from DRW_Interface and implement the required virtual methods to process header, table, and entity data. Ensure all virtual methods are defined to handle the specific data types encountered during parsing.

```cpp
#include "drw_interface.h"
#include <vector>

class MyDxfInterface : public DRW_Interface {
private:
    std::vector<DRW_Line> lines;
    std::vector<DRW_Circle> circles;
    std::vector<DRW_Layer> layers;
    DRW_Header header;

public:
    // Header callback - called when header section is parsed
    void addHeader(const DRW_Header* data) override {
        header = *data;
    }

    // Table callbacks
    void addLType(const DRW_LType& data) override {
        std::cout << "LineType: " << data.name << std::endl;
    }

    void addLayer(const DRW_Layer& data) override {
        layers.push_back(data);
        std::cout << "Layer: " << data.name << " Color: " << data.color << std::endl;
    }

    void addDimStyle(const DRW_Dimstyle& data) override {
        std::cout << "DimStyle: " << data.name << std::endl;
    }

    void addVport(const DRW_Vport& data) override {}
    void addTextStyle(const DRW_Textstyle& data) override {}
    void addAppId(const DRW_AppId& data) override {}

    // Block callbacks
    void addBlock(const DRW_Block& data) override {
        std::cout << "Block: " << data.name << std::endl;
    }
    void setBlock(const int handle) override {}
    void endBlock() override {}

    // Entity callbacks - these receive parsed drawing entities
    void addPoint(const DRW_Point& data) override {
        std::cout << "Point at: " << data.basePoint.x << ", "
                  << data.basePoint.y << std::endl;
    }

    void addLine(const DRW_Line& data) override {
        lines.push_back(data);
        std::cout << "Line from (" << data.basePoint.x << "," << data.basePoint.y
                  << ") to (" << data.secPoint.x << "," << data.secPoint.y << ")" << std::endl;
    }

    void addCircle(const DRW_Circle& data) override {
        circles.push_back(data);
        std::cout << "Circle center: (" << data.basePoint.x << ","
                  << data.basePoint.y << ") radius: " << data.radious << std::endl;
    }

    void addArc(const DRW_Arc& data) override {
        std::cout << "Arc center: (" << data.basePoint.x << "," << data.basePoint.y
                  << ") start: " << data.staangle << " end: " << data.endangle << std::endl;
    }

    void addEllipse(const DRW_Ellipse& data) override {}
    void addRay(const DRW_Ray& data) override {}
    void addXline(const DRW_Xline& data) override {}
    void addLWPolyline(const DRW_LWPolyline& data) override {}
    void addPolyline(const DRW_Polyline& data) override {}
    void addSpline(const DRW_Spline* data) override {}
    void addKnot(const DRW_Entity& data) override {}
    void addInsert(const DRW_Insert& data) override {}
    void addTrace(const DRW_Trace& data) override {}
    void add3dFace(const DRW_3Dface& data) override {}
    void addSolid(const DRW_Solid& data) override {}
    void addMText(const DRW_MText& data) override {}
    void addText(const DRW_Text& data) override {}
    void addDimAlign(const DRW_DimAligned* data) override {}
    void addDimLinear(const DRW_DimLinear* data) override {}
    void addDimRadial(const DRW_DimRadial* data) override {}
    void addDimDiametric(const DRW_DimDiametric* data) override {}
    void addDimAngular(const DRW_DimAngular* data) override {}
    void addDimAngular3P(const DRW_DimAngular3p* data) override {}
    void addDimOrdinate(const DRW_DimOrdinate* data) override {}
    void addLeader(const DRW_Leader* data) override {}
    void addHatch(const DRW_Hatch* data) override {}
    void addViewport(const DRW_Viewport& data) override {}
    void addImage(const DRW_Image* data) override {}
    void linkImage(const DRW_ImageDef* data) override {}
    void addComment(const char* comment) override {}
    void addPlotSettings(const DRW_PlotSettings* data) override {}

    // Writer callbacks (implement for file export)
    void writeHeader(DRW_Header& data) override { data = header; }
    void writeBlocks() override {}
    void writeBlockRecords() override {}
    void writeEntities() override {}
    void writeLTypes() override {}
    void writeLayers() override {}
    void writeTextstyles() override {}
    void writeVports() override {}
    void writeDimstyles() override {}
    void writeObjects() override {}
    void writeAppId() override {}
};
```

--------------------------------

### Write Multi-line Text to DXF

Source: https://context7.com/librecad/libdxfrw/llms.txt

Use DRW_MText for multi-line text with advanced formatting. Use \P for paragraph breaks and specify direction and line spacing.

```cpp
DRW_MText mtext;
mtext.basePoint = DRW_Coord(100, 100, 0);
mtext.text = "Line 1\PLine 2\PLine 3";  // \P = paragraph break
mtext.height = 5.0;
mtext.secPoint = DRW_Coord(1, 0, 0);      // Direction vector
mtext.interlin = 1.0;                      // Line spacing factor
mtext.style = "STANDARD";
mtext.alignV = (DRW_Text::VAlign)DRW_MText::TopLeft;
mtext.layer = "MText";

dxfRW dxf("mtext.dxf");
dxf.writeMText(&mtext);
```

--------------------------------

### Implement DWG to DXF Conversion

Source: https://context7.com/librecad/libdxfrw/llms.txt

Uses the DRW_Interface to store drawing data in memory and perform file conversion. Ensure all required headers are included and memory is managed for entity pointers.

```cpp
#include <iostream>
#include <list>
#include "libdxfrw.h"
#include "libdwgr.h"
#include "drw_interface.h"

// Data storage class
class DrawingData {
public:
    DRW_Header header;
    std::list<DRW_Layer> layers;
    std::list<DRW_LType> lineTypes;
    std::list<DRW_Textstyle> textStyles;
    std::list<DRW_Dimstyle> dimStyles;
    std::list<DRW_Entity*> entities;

    ~DrawingData() {
        for (auto* e : entities) delete e;
    }
};

class Converter : public DRW_Interface {
private:
    DrawingData* data;
    dxfRW* writer;

public:
    Converter() : data(nullptr), writer(nullptr) {}

    bool convert(const std::string& input, const std::string& output,
                 DRW::Version version, bool binary) {
        data = new DrawingData();

        // Read input file
        bool success = false;
        std::string ext = input.substr(input.find_last_of(".") + 1);

        if (ext == "dwg" || ext == "DWG") {
            dwgR reader(input.c_str());
            success = reader.read(this, false);
        } else {
            dxfRW reader(input.c_str());
            success = reader.read(this, false);
        }

        if (!success) {
            std::cerr << "Failed to read: " << input << std::endl;
            delete data;
            return false;
        }

        // Write output file
        dxfRW dxfWriter(output.c_str());
        writer = &dxfWriter;
        success = dxfWriter.write(this, version, binary);

        delete data;
        return success;
    }

    // Reader callbacks
    void addHeader(const DRW_Header* h) override { data->header = *h; }
    void addLayer(const DRW_Layer& l) override { data->layers.push_back(l); }
    void addLType(const DRW_LType& lt) override { data->lineTypes.push_back(lt); }
    void addTextStyle(const DRW_Textstyle& ts) override { data->textStyles.push_back(ts); }
    void addDimStyle(const DRW_Dimstyle& ds) override { data->dimStyles.push_back(ds); }
    void addLine(const DRW_Line& e) override { data->entities.push_back(new DRW_Line(e)); }
    void addCircle(const DRW_Circle& e) override { data->entities.push_back(new DRW_Circle(e)); }
    void addArc(const DRW_Arc& e) override { data->entities.push_back(new DRW_Arc(e)); }
    void addLWPolyline(const DRW_LWPolyline& e) override { data->entities.push_back(new DRW_LWPolyline(e)); }
    void addText(const DRW_Text& e) override { data->entities.push_back(new DRW_Text(e)); }
    void addMText(const DRW_MText& e) override { data->entities.push_back(new DRW_MText(e)); }

    // Writer callbacks
    void writeHeader(DRW_Header& h) override { h = data->header; }
    void writeLayers() override {
        for (auto& l : data->layers) writer->writeLayer(&l);
    }
    void writeLTypes() override {
        for (auto& lt : data->lineTypes) writer->writeLineType(&lt);
    }
    void writeTextstyles() override {
        for (auto& ts : data->textStyles) writer->writeTextstyle(&ts);
    }
    void writeDimstyles() override {
        for (auto& ds : data->dimStyles) writer->writeDimstyle(&ds);
    }
    void writeEntities() override {
        for (auto* e : data->entities) {
            switch (e->eType) {
                case DRW::LINE: writer->writeLine(static_cast<DRW_Line*>(e)); break;
                case DRW::CIRCLE: writer->writeCircle(static_cast<DRW_Circle*>(e)); break;
                case DRW::ARC: writer->writeArc(static_cast<DRW_Arc*>(e)); break;
                case DRW::LWPOLYLINE: writer->writeLWPolyline(static_cast<DRW_LWPolyline*>(e)); break;
                case DRW::TEXT: writer->writeText(static_cast<DRW_Text*>(e)); break;
                case DRW::MTEXT: writer->writeMText(static_cast<DRW_MText*>(e)); break;
                default: break;
            }
        }
    }

    // Stub implementations for remaining callbacks
    void addVport(const DRW_Vport&) override {}
    void addAppId(const DRW_AppId&) override {}
    void addBlock(const DRW_Block&) override {}
    void setBlock(const int) override {}
    void endBlock() override {}
    void addPoint(const DRW_Point&) override {}
    void addRay(const DRW_Ray&) override {}
    void addXline(const DRW_Xline&) override {}
    void addEllipse(const DRW_Ellipse&) override {}
    void addPolyline(const DRW_Polyline&) override {}
    void addSpline(const DRW_Spline*) override {}
    void addKnot(const DRW_Entity&) override {}
    void addInsert(const DRW_Insert&) override {}
    void addTrace(const DRW_Trace&) override {}
    void add3dFace(const DRW_3Dface&) override {}
    void addSolid(const DRW_Solid&) override {}
    void addDimAlign(const DRW_DimAligned*) override {}
    void addDimLinear(const DRW_DimLinear*) override {}
    void addDimRadial(const DRW_DimRadial*) override {}
    void addDimDiametric(const DRW_DimDiametric*) override {}
    void addDimAngular(const DRW_DimAngular*) override {}
```

--------------------------------

### Create DRW_Circle Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Defines a circle with a center point and radius.

```cpp
DRW_Circle circle;
circle.basePoint = DRW_Coord(50, 50, 0);  // Center point
circle.radious = 25.0;                     // Radius
circle.thickness = 0.0;
circle.layer = "Circles";
circle.color = 3;  // Green

dxfRW dxf("circles.dxf");
dxf.writeCircle(&circle);
```

--------------------------------

### Define Linetype Pattern

Source: https://context7.com/librecad/libdxfrw/llms.txt

Create a custom linetype with dash and space sequences. The `path` vector defines the pattern, where positive values are dashes and negative values are spaces. The `length` property specifies the total pattern length.

```cpp
DRW_LType ltype;
ltype.name = "DASHED";
ltype.desc = "Dashed line __ __ __";
ltype.length = 0.75;

// Pattern: positive = dash, negative = space
ltype.path.push_back(0.5);
// Dash
ltype.path.push_back(-0.25);
// Space
ltype.size = ltype.path.size();

dxfRW dxf("linetypes.dxf");
dxf.writeLineType(&ltype);
```

--------------------------------

### Create DRW_Line Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Defines a line segment using two endpoints and writes it to a DXF file.

```cpp
DRW_Line line;
line.basePoint = DRW_Coord(0, 0, 0);      // Start point
line.secPoint = DRW_Coord(100, 200, 0);   // End point
line.layer = "Lines";
line.lineType = "CONTINUOUS";
line.color = 1;  // Red
line.lWeight = DRW_LW_Conv::width06;  // 0.20mm

dxfRW dxf("lines.dxf");
dxf.writeLine(&line);
```

--------------------------------

### Implement DRW_Interface Callbacks

Source: https://context7.com/librecad/libdxfrw/llms.txt

Override these methods in a class inheriting from DRW_Interface to handle specific CAD entities and file operations.

```cpp
    void addDimAngular3P(const DRW_DimAngular3p*) override {}
    void addDimOrdinate(const DRW_DimOrdinate*) override {}
    void addLeader(const DRW_Leader*) override {}
    void addHatch(const DRW_Hatch*) override {}
    void addViewport(const DRW_Viewport&) override {}
    void addImage(const DRW_Image*) override {}
    void linkImage(const DRW_ImageDef*) override {}
    void addComment(const char*) override {}
    void addPlotSettings(const DRW_PlotSettings*) override {}
    void writeBlocks() override {}
    void writeBlockRecords() override {}
    void writeVports() override {}
    void writeObjects() override {}
    void writeAppId() override {}
};
```

--------------------------------

### Write Dimension Types to DXF

Source: https://context7.com/librecad/libdxfrw/llms.txt

Create and write various dimension types including aligned, linear, and radial dimensions. Set definition points, dimension points, and styles.

```cpp
// Aligned dimension
DRW_DimAligned dimAligned;
dimAligned.setDef1Point(DRW_Coord(0, 0, 0));    // First definition point
dimAligned.setDef2Point(DRW_Coord(100, 0, 0));  // Second definition point
dimAligned.setDimPoint(DRW_Coord(50, 20, 0));   // Dimension line location
dimAligned.setStyle("STANDARD");
dimAligned.layer = "Dimensions";

// Linear dimension with angle
DRW_DimLinear dimLinear;
dimLinear.setDef1Point(DRW_Coord(0, 0, 0));
dimLinear.setDef2Point(DRW_Coord(100, 50, 0));
dimLinear.setDimPoint(DRW_Coord(50, 80, 0));
dimLinear.setAngle(0.0);    // Horizontal measurement
dimLinear.setStyle("STANDARD");

// Radial dimension
DRW_DimRadial dimRadial;
dimRadial.setCenterPoint(DRW_Coord(100, 100, 0));
dimRadial.setDiameterPoint(DRW_Coord(150, 100, 0));
dimRadial.setLeaderLength(15.0);
dimRadial.setStyle("STANDARD");

dxfRW dxf("dimensions.dxf");
dxf.writeDimension(&dimAligned);
dxf.writeDimension(&dimLinear);
dxf.writeDimension(&dimRadial);
```

--------------------------------

### Create DRW_Polyline Entity

Source: https://context7.com/librecad/libdxfrw/llms.txt

Defines a 3D polyline with 3D vertices.

```cpp
DRW_Polyline polyline;
polyline.layer = "3DPolylines";
polyline.flags = 8;  // 8 = 3D polyline

// Add 3D vertices
DRW_Vertex v1(0, 0, 0, 0);       // x, y, z, bulge
DRW_Vertex v2(100, 0, 50, 0);
DRW_Vertex v3(100, 100, 100, 0);
DRW_Vertex v4(0, 100, 50, 0);

polyline.addVertex(v1);
polyline.addVertex(v2);
polyline.addVertex(v3);
polyline.addVertex(v4);

dxfRW dxf("polyline3d.dxf");
dxf.writePolyline(&polyline);
```

--------------------------------

### Define Text Style

Source: https://context7.com/librecad/libdxfrw/llms.txt

Define a text style by specifying the font file, height, width factor, oblique angle, and generation flags. A height of 0.0 indicates variable height. Generation flags can be used for mirroring.

```cpp
DRW_Textstyle style;
style.name = "MyStyle";
style.font = "arial.ttf";
// Font file
style.height = 0.0;
// 0 = variable height
style.width = 1.0;
// Width factor
style.oblique = 0.0;
// Oblique angle
style.genFlag = 0;
// 2 = X mirror, 4 = Y mirror

dxfRW dxf("textstyles.dxf");
dxf.writeTextstyle(&style);
```

--------------------------------

### Write Block Insert to DXF

Source: https://context7.com/librecad/libdxfrw/llms.txt

Use DRW_Insert to add a block reference to the drawing. Specify the block name, insertion point, scale, rotation, and array properties.

```cpp
DRW_Insert insert;
insert.name = "MyBlock";                   // Block name to insert
insert.basePoint = DRW_Coord(200, 200, 0); // Insertion point
insert.xscale = 1.0;
insert.yscale = 1.0;
insert.zscale = 1.0;
insert.angle = M_PI / 4;                   // 45 degrees in radians
insert.colcount = 1;                       // Array columns
insert.rowcount = 1;                       // Array rows
insert.colspace = 0;                       // Column spacing
insert.rowspace = 0;                       // Row spacing
insert.layer = "Inserts";

dxfRW dxf("inserts.dxf");
dxf.writeInsert(&insert);
```

--------------------------------

### Define Dimension Style

Source: https://context7.com/librecad/libdxfrw/llms.txt

Configure a dimension style with various formatting options including arrow size, text height, extension line settings, and colors. The `dimscale` property controls the overall scale factor.

```cpp
DRW_Dimstyle dimstyle;
dimstyle.name = "MyDimStyle";
dimstyle.dimtxsty = "STANDARD";
// Text style
dimstyle.dimasz = 0.18;
// Arrow size
dimstyle.dimtxt = 0.18;
// Text height
dimstyle.dimexe = 0.18;
// Extension line extension
dimstyle.dimexo = 0.0625;
// Extension line offset
dimstyle.dimgap = 0.09;
// Gap between dimension line and text
dimstyle.dimscale = 1.0;
// Overall scale factor
dimstyle.dimtad = 1;
// Text above dimension line
dimstyle.dimclrd = 256;
// Dimension line color (BYLAYER)
dimstyle.dimclre = 256;
// Extension line color
dimstyle.dimclrt = 256;
// Text color

dxfRW dxf("dimstyles.dxf");
dxf.writeDimstyle(&dimstyle);
```

--------------------------------

### Write DXF to Specific Version

Source: https://context7.com/librecad/libdxfrw/llms.txt

Write a DXF file to a specific AutoCAD version using the `DRW::Version` constants. You can choose between ASCII and binary formats.

```cpp
// Available version constants
// DRW::UNKNOWNV    // Unknown version
// DRW::AC1009      // AutoCAD R11/R12
// DRW::AC1012      // AutoCAD R13
// DRW::AC1014      // AutoCAD R14
// DRW::AC1015      // AutoCAD 2000/2002 (recommended for compatibility)
// DRW::AC1018      // AutoCAD 2004/2005/2006
// DRW::AC1021      // AutoCAD 2007/2008/2009
// DRW::AC1024      // AutoCAD 2010/2011/2012
// DRW::AC1027      // AutoCAD 2013-2017
// DRW::AC1032      // AutoCAD 2018-2020

// Example: Write to specific version
dxfRW dxf("output.dxf");
dxf.write(&interface, DRW::AC1015, false);  // ASCII AutoCAD 2000
dxf.write(&interface, DRW::AC1015, true);   // Binary AutoCAD 2000
```