particle/progress-bar: renders a progrss-bar-like thingy

particles/progress_bar.c

@@ -0,0 +1,150 @@
+#include "progress_bar.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+struct private {
+    char *tag;
+    int width;
+
+    struct particle *start_marker;
+    struct particle *end_marker;
+    struct particle *fill;
+    struct particle *empty;
+    struct particle *indicator;
+};
+
+struct exposable_private {
+    size_t count;
+    struct exposable **exposables;
+};
+
+static void
+particle_destroy(struct particle *particle)
+{
+    struct private *p = particle->private;
+
+    p->start_marker->destroy(p->start_marker);
+    p->end_marker->destroy(p->end_marker);
+    p->fill->destroy(p->fill);
+    p->empty->destroy(p->empty);
+    p->indicator->destroy(p->indicator);
+
+    free(p->tag);
+    free(p);
+    particle_default_destroy(particle);
+}
+
+static void
+exposable_destroy(struct exposable *exposable)
+{
+    struct exposable_private *e = exposable->private;
+    for (size_t i = 0; i < e->count; i++)
+        e->exposables[i]->destroy(e->exposables[i]);
+    free(e->exposables);
+    free(e);
+    free(exposable);
+}
+
+static int
+begin_expose(struct exposable *exposable, cairo_t *cr)
+{
+    struct exposable_private *e = exposable->private;
+
+    /* Margins */
+    exposable->width = exposable->particle->left_margin +
+        exposable->particle->right_margin;
+
+    /* Sub-exposables */
+    for (size_t i = 0; i < e->count; i++)
+        exposable->width += e->exposables[i]->begin_expose(e->exposables[i], cr);
+
+    return exposable->width;
+}
+
+static void
+expose(const struct exposable *exposable, cairo_t *cr, int x, int y, int height)
+{
+    const struct exposable_private *e = exposable->private;
+
+    const struct deco *deco = exposable->particle->deco;
+    if (deco != NULL)
+        deco->expose(deco, cr, x, y, exposable->width, height);
+
+    x += exposable->particle->left_margin;
+    for (size_t i = 0; i < e->count; i++) {
+        e->exposables[i]->expose(e->exposables[i], cr, x, y, height);
+        x += e->exposables[i]->width;
+    }
+}
+
+static struct exposable *
+instantiate(const struct particle *particle, const struct tag_set *tags)
+{
+    const struct private *p = particle->private;
+    const struct tag *tag = tag_for_name(tags, p->tag);
+    assert(tag != NULL);
+
+    long value = tag->as_int(tag);
+    long min = tag->min(tag);
+    long max = tag->max(tag);
+
+    long fill_count = max == min ? 0 : p->width * value / (max - min);
+    long empty_count = p->width - fill_count;
+
+    struct exposable_private *epriv = malloc(sizeof(*epriv));
+    epriv->count = (
+        1 +             /* Start marker */
+        fill_count +    /* Before current position */
+        1 +             /* Current position indicator */
+        empty_count +   /* After current position */
+        1);             /* End marker */
+
+    epriv->exposables = malloc(epriv->count * sizeof(epriv->exposables[0]));
+
+    size_t idx = 0;
+    epriv->exposables[idx++] = p->start_marker->instantiate(p->start_marker, tags);
+    for (size_t i = 0; i < fill_count; i++)
+        epriv->exposables[idx++] = p->fill->instantiate(p->fill, tags);
+    epriv->exposables[idx++] = p->indicator->instantiate(p->indicator, tags);
+    for (size_t i = 0; i < empty_count; i++)
+        epriv->exposables[idx++] = p->empty->instantiate(p->empty, tags);
+    epriv->exposables[idx++] = p->end_marker->instantiate(p->end_marker, tags);
+
+    assert(idx == epriv->count);
+
+    struct exposable *exposable = malloc(sizeof(*exposable));
+    exposable->particle = particle;
+    exposable->private = epriv;
+    exposable->destroy = &exposable_destroy;
+    exposable->begin_expose = &begin_expose;
+    exposable->expose = &expose;
+
+    return exposable;
+}
+
+struct particle *
+particle_progress_bar_new(const char *tag, int width,
+                          struct particle *start_marker,
+                          struct particle *end_marker,
+                          struct particle *fill, struct particle *empty,
+                          struct particle *indicator,
+                          int left_margin, int right_margin)
+{
+    struct private *priv = malloc(sizeof(*priv));
+    priv->tag = strdup(tag);
+    priv->width = width;
+    priv->start_marker = start_marker;
+    priv->end_marker = end_marker;
+    priv->fill = fill;
+    priv->empty = empty;
+    priv->indicator = indicator;
+
+    struct particle *particle = particle_common_new(left_margin, right_margin);
+    particle->private = priv;
+    particle->destroy = &particle_destroy;
+    particle->instantiate = &instantiate;
+
+    return particle;
+}