JNIPangoLayout.cpp

// JNI to Pango Text Layout interface
// Copyright 2014 (C) Ralph Thomas, Palo Alto, CA

#include "JNIRegister.h"
#include <pango/pango-layout.h>
#include <text/pango/ViewdoPangoRenderer.h>
#include <text/pango/ViewdoGLRenderer.h>

static const char* JAVA_CLASS = "com/infinite_imagination/text/PangoTextLayout";

static PangoContext* sContext = nullptr;
static PangoFontMap* sFontMap = nullptr;

static PangoContext* context() {
    if (sContext) return sContext;
    sContext = pango_context_new();
    sFontMap = pango_ft2_font_map_new();
    pango_context_set_font_map(sContext, sFontMap);

    return sContext;
}

struct JNIPangoLayout {
    std::vector<ViewdoTextRun> m_runs;
    PangoLayout* m_layout;

    JNIPangoLayout() 
        : m_layout(pango_layout_new(context()))
    {}
    ~JNIPangoLayout() {
        g_object_unref(m_layout);
    }

    void setMarkup(const char* markup) { pango_layout_set_markup(m_layout, markup, -1); }
    void setWidth(int width) { pango_layout_set_width(m_layout, width); }
    void setJustify(bool justify) { pango_layout_set_justify(m_layout, justify); }
    void setAlignment(int alignment) { pango_layout_set_alignment(m_layout, (PangoAlignment) alignment); }
    void getPixelSize(int* width, int* height) { pango_layout_get_pixel_size(m_layout, width, height); }
    void setFontDescription(PangoFontDescription* d) { pango_layout_set_font_description(m_layout, d); }
    void generateGeometry(float x, float y, float scale) {
        m_runs.clear();
        viewdo_pango_render(m_layout, x, y, scale, m_runs);
    }
    void render(int colorUniform, float opacity) { viewdo_pango_gl_render(m_runs, colorUniform, opacity); }
};

static jlong pl_create() {
    return reinterpret_cast<jlong>(new JNIPangoLayout());
}
static void pl_destroy(JNIEnv*, jclass, jlong obj) {
    if (obj) delete reinterpret_cast<JNIPangoLayout*>(obj);
}
static void pl_setMarkup(JNIEnv* env, jclass, jlong obj, jstring markup) {
    if (!obj) return;
    JNIPangoLayout* layout = reinterpret_cast<JNIPangoLayout*>(obj);
    if (!markup) {
        layout->setMarkup("");
        return;
    }
    const char* str = env->GetStringUTFChars(markup, nullptr);
    layout->setMarkup(str);
    env->ReleaseStringUTFChars(markup, str);
}
static void pl_setWidth(JNIEnv*, jclass, jlong obj, int width) {
    if (obj) reinterpret_cast<JNIPangoLayout*>(obj)->setWidth(width);
}
static void pl_setJustify(JNIEnv*, jclass, jlong obj, bool justify) {
    if (obj) reinterpret_cast<JNIPangoLayout*>(obj)->setJustify(justify);
}
static void pl_setAlignment(JNIEnv*, jclass, jlong obj, int alignment) {
    if (obj) reinterpret_cast<JNIPangoLayout*>(obj)->setAlignment(alignment);
}
static void pl_setFontDescription(JNIEnv*, jclass, jlong obj, jlong font) {
    if (obj) reinterpret_cast<JNIPangoLayout*>(obj)->setFontDescription(reinterpret_cast<PangoFontDescription*>(font));
}
static void pl_getPixelSize(JNIEnv* env, jclass, jlong obj, jintArray out) {
    if (!obj || !out) return;
    JNIPangoLayout* layout = reinterpret_cast<JNIPangoLayout*>(obj);
    jint* outArray = env->GetIntArrayElements(out, nullptr);
    layout->getPixelSize(outArray, outArray+1);
    env->ReleaseIntArrayElements(out, outArray, 0);
}
static void pl_generateGeometry(JNIEnv*, jclass, jlong obj, float x, float y, float scale) {
    if (obj) reinterpret_cast<JNIPangoLayout*>(obj)->generateGeometry(x, y, scale);
}
static void pl_render(JNIEnv*, jclass, jlong obj, int colorUniform, float opacity) {
    if (obj) reinterpret_cast<JNIPangoLayout*>(obj)->render(colorUniform, opacity);
}


static LPNativeMethod methods[] = {
    "create",           "()J",                      (void*) pl_create,
    "destroy",          "(J)V",                     (void*) pl_destroy,
    "setMarkup",        "(JLjava/lang/String;)V",   (void*) pl_setMarkup,
    "setWidth",         "(JI)V",                    (void*) pl_setWidth,
    "setJustify",       "(JZ)V",                    (void*) pl_setJustify,
    "setAlignment",     "(JI)V",                    (void*) pl_setAlignment,
    "setFontDescription","(JJ)V",                   (void*) pl_setFontDescription,
    "getPixelSize",     "(J[I)V",                   (void*) pl_getPixelSize,
    "generateGeometry", "(JFFF)V",                  (void*) pl_generateGeometry,
    "render",           "(JIF)V",                   (void*) pl_render,
    "contextLost",      "()V",                      (void*) viewdo_pango_gl_context_lost
};

jint JNIRegisterPangoLayout(JNIEnv* env) {
    return LPRegisterNatives(env, env->FindClass(JAVA_CLASS), methods);
}