Carla/source/modules/dgl/CairoWidget.hpp

/*
 * DISTRHO Plugin Framework (DPF)
 * Copyright (C) 2012-2014 Filipe Coelho <falktx@falktx.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any purpose with
 * or without fee is hereby granted, provided that the above copyright notice and this
 * permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
 * TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN
 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef DGL_CAIRO_WIDGET_HPP_INCLUDED
#define DGL_CAIRO_WIDGET_HPP_INCLUDED

#include "Widget.hpp"

#include <cairo.h>

#include <cstdio>

START_NAMESPACE_DGL

// -----------------------------------------------------------------------

class CairoWidget : public Widget
{
public:
    CairoWidget(Window& parent)
        : Widget(parent),
          fContext(nullptr),
          fSurface(nullptr),
          fTextureId(0)
    {
    }

    virtual void setWidth(int width) override
    {
        if (fArea.getWidth() == width)
            return;

        Widget::setWidth(width);
        _recreateSurface();
    }

    virtual void setHeight(int height) override
    {
        if (fArea.getHeight() == height)
            return;

        Widget::setHeight(height);
        _recreateSurface();
    }

    virtual void setSize(const Size<int>& size) override
    {
        if (fArea.getSize() == size)
            return;

        Widget::setSize(size);
        _recreateSurface();
    }

    void setSize(int width, int height)
    {
        setSize(Size<int>(width, height));
    }

protected:
    virtual void cairoDisplay(cairo_t* const context) = 0;

private:
    void onDisplay() override
    {
        // wait for sizing
        if (fSurface == nullptr || fContext == nullptr)
        {
            printf("invalid surface\n");
            return;
        }

        if (fTextureId == 0)
            glGenTextures(1, &fTextureId);
        if (fTextureId == 0)
        {
            // TODO: invalidate widget
            printf("invalid texture\n");
            return;
        }

#if 1
        const int x = getX();
        const int y = getY();
        const int width  = getWidth();
        const int height = getHeight();

        // draw cairo stuff
        cairoDisplay(fContext);

        // get cairo surface data (RGB24)
        unsigned char* const surfaceData = cairo_image_surface_get_data(fSurface);

        // enable GL texture
        glEnable(GL_TEXTURE_RECTANGLE_ARB);

        // set texture params
        glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
        glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
        glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

        // bind texture to surface data
        glBindTexture(GL_TEXTURE_RECTANGLE_ARB, fTextureId);
        glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, surfaceData);

        // draw the texture

//         glBegin(GL_QUADS);
//           glTexCoord2f(0.0f, 0.0f);
//           glVertex2i(x, y);
//
//           glTexCoord2f(1.0f, 0.0f);
//           glVertex2i(x+width, y);
//
//           glTexCoord2f(1.0f, 1.0f);
//           glVertex2i(x+width, y+height);
//
//           glTexCoord2f(0.0f, 1.0f);
//           glVertex2i(x, y+height);
//         glEnd();

        glBegin(GL_QUADS);
          //glTexCoord2i(x, y);
          glTexCoord2i(0, 0);
          glVertex2i(x, y);

          //glTexCoord2i(x+width, y);
          glTexCoord2i(width, 0);
          glVertex2i(x+width, y);

          //glTexCoord2i(x+width, y+height);
          glTexCoord2i(width, height);
          glVertex2i(x+width, y+height);

          //glTexCoord2i(x, y+height);
          glTexCoord2i(0, height);
          glVertex2i(x, y+height);
        glEnd();

        // cleanup
        glBindTexture(GL_TEXTURE_RECTANGLE_ARB, 0);
        glDisable(GL_TEXTURE_RECTANGLE_ARB);
#endif
    }

    void onClose() override
    {
        if (fContext != nullptr)
        {
            cairo_destroy(fContext);
            fContext = nullptr;
        }

        if (fSurface != nullptr)
        {
            cairo_surface_destroy(fSurface);
            fSurface = nullptr;
        }

        if (fTextureId != 0)
        {
            glDeleteTextures(1, &fTextureId);
            fTextureId = 0;
        }
    }

    void _recreateSurface()
    {
        if (fContext != nullptr)
            cairo_destroy(fContext);

        if (fSurface != nullptr)
            cairo_surface_destroy(fSurface);

        fSurface = cairo_image_surface_create(CAIRO_FORMAT_RGB24, fArea.getWidth(), fArea.getHeight());

        if (fSurface != nullptr)
            fContext = cairo_create(fSurface);
        else
           fContext = nullptr;
    }

private:
    cairo_t*         fContext;
    cairo_surface_t* fSurface;
    GLuint           fTextureId;
};

// -----------------------------------------------------------------------

END_NAMESPACE_DGL

#endif // DGL_CAIRO_WIDGET_HPP_INCLUDED