gvtextlayout_quartz.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
#include "config.h"
 
#include <stdbool.h>
#include <stdlib.h>
#include <TargetConditionals.h>
 
#include <gvc/gvplugin_textlayout.h>
#include "gvplugin_quartz.h"
 
#if TARGET_OS_IPHONE
#include <CoreText/CoreText.h>
#endif
 
void *quartz_new_layout(char* fontname, double fontsize, char* text)
{
        CFStringRef fontnameref = CFStringCreateWithCString(NULL, fontname, kCFStringEncodingUTF8);
        CFStringRef textref = CFStringCreateWithCString(NULL, text, kCFStringEncodingUTF8);
        CTLineRef line = NULL;
        
        if (fontnameref && textref) {
                /* set up the Core Text line */
                CTFontRef font = CTFontCreateWithName(fontnameref, fontsize, NULL);
                const void *attributeNames[] = {
                  kCTFontAttributeName, kCTForegroundColorFromContextAttributeName};
                const void *attributeValues[] = {font, kCFBooleanTrue};
                CFDictionaryRef attributes = CFDictionaryCreate(
                        NULL,
                        attributeNames,
                        attributeValues,
                        sizeof(attributeNames) / sizeof(attributeNames[0]),
                        &kCFTypeDictionaryKeyCallBacks,
                        &kCFTypeDictionaryValueCallBacks);
                CFAttributedStringRef attributed = CFAttributedStringCreate(NULL, textref, attributes);
                line = CTLineCreateWithAttributedString(attributed);
                
                CFRelease(attributed);
                CFRelease(attributes);
                CFRelease(font);
        }
        
        if (textref)
                CFRelease(textref);
        if (fontnameref)
                CFRelease(fontnameref);
// Suppress Clang/GCC -Wcast-qual warning. Casting away const here is acceptable
// as we do not intend to modify the target through the resulting non-const
// pointer. We need a non-const pointer simply to satisfy the type of
// `textspan_t.layout`.
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-qual"
#endif
        return (void *)line;
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
}
 
void quartz_size_layout(void *layout, double* width, double* height, double* yoffset_layout)
{
        /* get the typographic bounds */
        CGFloat ascent = 0.0;
        CGFloat descent = 0.0;
        CGFloat leading = 0.0;
        
        *width = CTLineGetTypographicBounds(layout, &ascent, &descent, &leading);
        *height = ascent + descent + leading;
        *yoffset_layout = ascent;
}
 
void quartz_draw_layout(void *layout, CGContextRef context, CGPoint position)
{
        CGContextSetTextPosition(context, position.x, position.y);
        CTLineDraw(layout, context);
}
 
void quartz_free_layout(void *layout)
{
        if (layout)
                CFRelease(layout);
}
 
static bool quartz_textlayout(textspan_t *para, char **fontpath)
{
        (void)fontpath;
 
        void *line = quartz_new_layout(para->font->name, para->font->size, para->str);
        if (line)
        {
                /* report the layout */
                para->layout = line;
                para->free_layout = &quartz_free_layout;
                quartz_size_layout(line, &para->size.x, &para->size.y, &para->yoffset_layout);
                para->yoffset_centerline = 0.2 * para->font->size;
                return true;
        }
        else
                return false;
};
 
static gvtextlayout_engine_t quartz_textlayout_engine = {
    quartz_textlayout
};
 
gvplugin_installed_t gvtextlayout_quartz_types[] = {
    {0, "textlayout", 8, &quartz_textlayout_engine, NULL},
    {0, NULL, 0, NULL, NULL}
};