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-rw-r--r--pango2/pangocairo-context.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/pango2/pangocairo-context.c b/pango2/pangocairo-context.c
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+/* Pango2
+ * pangocairo-context.c: Cairo context handling
+ *
+ * Copyright (C) 2000-2005 Red Hat Software
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include "pangocairo.h"
+#include "pangocairo-private.h"
+#include "pango-impl-utils.h"
+#include "pango-context-private.h"
+
+#include <string.h>
+
+/**
+ * pango2_cairo_update_context:
+ * @cr: a Cairo context
+ * @context: a `Pango2Context`, from a pangocairo font map
+ *
+ * Updates a `Pango2Context` previously created for use with Cairo to
+ * match the current transformation and target surface of a Cairo
+ * context.
+ *
+ * If any layouts have been created for the context, it's necessary
+ * to call [method@Pango2.Layout.context_changed] on those layouts.
+ */
+void
+pango2_cairo_update_context (cairo_t *cr,
+ Pango2Context *context)
+{
+ cairo_matrix_t cairo_matrix;
+ cairo_surface_t *target;
+ Pango2Matrix pango2_matrix;
+ const Pango2Matrix *current_matrix, identity_matrix = PANGO2_MATRIX_INIT;
+ const cairo_font_options_t *merged_options;
+ cairo_font_options_t *old_merged_options;
+ gboolean changed = FALSE;
+
+ g_return_if_fail (cr != NULL);
+ g_return_if_fail (PANGO2_IS_CONTEXT (context));
+
+ target = cairo_get_target (cr);
+
+ if (!context->surface_options)
+ context->surface_options = cairo_font_options_create ();
+ cairo_surface_get_font_options (target, context->surface_options);
+ if (!context->set_options_explicit)
+ {
+ if (!context->set_options)
+ context->set_options = cairo_font_options_create ();
+ cairo_get_font_options (cr, context->set_options);
+ }
+
+ old_merged_options = context->merged_options;
+ context->merged_options = NULL;
+
+ merged_options = pango2_cairo_context_get_merged_font_options (context);
+
+ if (old_merged_options)
+ {
+ if (!cairo_font_options_equal (merged_options, old_merged_options))
+ changed = TRUE;
+ cairo_font_options_destroy (old_merged_options);
+ old_merged_options = NULL;
+ }
+ else
+ changed = TRUE;
+
+ cairo_get_matrix (cr, &cairo_matrix);
+ pango2_matrix.xx = cairo_matrix.xx;
+ pango2_matrix.yx = cairo_matrix.yx;
+ pango2_matrix.xy = cairo_matrix.xy;
+ pango2_matrix.yy = cairo_matrix.yy;
+ pango2_matrix.x0 = 0;
+ pango2_matrix.y0 = 0;
+
+ current_matrix = pango2_context_get_matrix (context);
+ if (!current_matrix)
+ current_matrix = &identity_matrix;
+
+ /* layout is matrix-independent if metrics-hinting is off.
+ * also ignore matrix translation offsets
+ */
+ if ((cairo_font_options_get_hint_metrics (merged_options) != CAIRO_HINT_METRICS_OFF) &&
+ (0 != memcmp (&pango2_matrix, current_matrix, sizeof (Pango2Matrix))))
+ changed = TRUE;
+
+ pango2_context_set_matrix (context, &pango2_matrix);
+
+ if (changed)
+ pango2_context_changed (context);
+}
+
+/**
+ * pango2_cairo_context_set_font_options:
+ * @context: a `Pango2Context`, from a pangocairo font map
+ * @options: (nullable): a `cairo_font_options_t`, or %NULL to unset
+ * any previously set options. A copy is made.
+ *
+ * Sets the font options used when rendering text with this context.
+ *
+ * These options override any options that [func@Pango2.cairo_update_context]
+ * derives from the target surface.
+ */
+void
+pango2_cairo_context_set_font_options (Pango2Context *context,
+ const cairo_font_options_t *options)
+{
+ g_return_if_fail (PANGO2_IS_CONTEXT (context));
+
+ if (!context->set_options && !options)
+ return;
+
+ if (context->set_options && options &&
+ cairo_font_options_equal (context->set_options, options))
+ return;
+
+ if (context->set_options || options)
+ pango2_context_changed (context);
+
+ if (context->set_options)
+ cairo_font_options_destroy (context->set_options);
+
+ if (options)
+ {
+ context->set_options = cairo_font_options_copy (options);
+ context->set_options_explicit = TRUE;
+ }
+ else
+ {
+ context->set_options = NULL;
+ context->set_options_explicit = FALSE;
+ }
+
+ if (context->merged_options)
+ {
+ cairo_font_options_destroy (context->merged_options);
+ context->merged_options = NULL;
+ }
+}
+
+/**
+ * pango2_cairo_context_get_font_options:
+ * @context: a `Pango2Context`, from a pangocairo font map
+ *
+ * Retrieves any font rendering options previously set with
+ * [func@Pango2.cairo_context_set_font_options].
+ *
+ * This function does not report options that are derived from
+ * the target surface by [func@Pango2.cairo_update_context].
+ *
+ * Return value: (nullable): the font options previously set on the
+ * context, or %NULL if no options have been set. This value is
+ * owned by the context and must not be modified or freed.
+ */
+const cairo_font_options_t *
+pango2_cairo_context_get_font_options (Pango2Context *context)
+{
+ g_return_val_if_fail (PANGO2_IS_CONTEXT (context), NULL);
+
+ return context->set_options;
+}
+
+const cairo_font_options_t *
+pango2_cairo_context_get_merged_font_options (Pango2Context *context)
+{
+ if (!context->merged_options)
+ {
+ context->merged_options = cairo_font_options_create ();
+
+ if (context->surface_options)
+ cairo_font_options_merge (context->merged_options, context->surface_options);
+ if (context->set_options)
+ cairo_font_options_merge (context->merged_options, context->set_options);
+ }
+
+ return context->merged_options;
+}
+
+/**
+ * pango2_cairo_create_context:
+ * @cr: a Cairo context
+ *
+ * Creates a context object set up to match the current transformation
+ * and target surface of the Cairo context.
+ *
+ * This context can then be
+ * used to create a layout using [ctor@Pango2.Layout.new].
+ *
+ * This function is a convenience function that creates a context
+ * using the default font map, then updates it to @cr.
+ *
+ * Return value: (transfer full): the newly created `Pango2Context`
+ */
+Pango2Context *
+pango2_cairo_create_context (cairo_t *cr)
+{
+ Pango2Context *context;
+
+ g_return_val_if_fail (cr != NULL, NULL);
+
+ context = pango2_context_new ();
+ pango2_cairo_update_context (cr, context);
+
+ return context;
+}
+
+/**
+ * pango2_cairo_update_layout:
+ * @cr: a Cairo context
+ * @layout: a `Pango2Layout`
+ *
+ * Updates the private `Pango2Context` of a `Pango2Layout` to match
+ * the current transformation and target surface of a Cairo context.
+ */
+void
+pango2_cairo_update_layout (cairo_t *cr,
+ Pango2Layout *layout)
+{
+ g_return_if_fail (cr != NULL);
+ g_return_if_fail (PANGO2_IS_LAYOUT (layout));
+
+ pango2_cairo_update_context (cr, pango2_layout_get_context (layout));
+}
+
+/**
+ * pango2_cairo_create_layout:
+ * @cr: a Cairo context
+ *
+ * Creates a layout object set up to match the current transformation
+ * and target surface of the Cairo context.
+ *
+ * This layout can then be used for text measurement with functions
+ * like [method@Pango2.Lines.get_size] or drawing with functions like
+ * [func@Pango2.cairo_show_layout]. If you change the transformation or target
+ * surface for @cr, you need to call [func@Pango2.cairo_update_layout].
+ *
+ * This function is the most convenient way to use Cairo with Pango2,
+ * however it is slightly inefficient since it creates a separate
+ * `Pango2Context` object for each layout. This might matter in an
+ * application that was laying out large amounts of text.
+ *
+ * Return value: (transfer full): the newly created `Pango2Layout`
+ */
+Pango2Layout *
+pango2_cairo_create_layout (cairo_t *cr)
+{
+ Pango2Context *context;
+ Pango2Layout *layout;
+
+ g_return_val_if_fail (cr != NULL, NULL);
+
+ context = pango2_cairo_create_context (cr);
+ layout = pango2_layout_new (context);
+ g_object_unref (context);
+
+ return layout;
+}
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