From: Scott Worley Date: Fri, 24 Feb 2023 04:58:33 +0000 (-0800) Subject: Extract to_screen() X-Git-Url: http://git.scottworley.com/batteryviewer/commitdiff_plain/487d9d1f8b385fb4ba6accc34565fb6a067cb0e2?hp=328956d5fb25e7ea8aae4f0d35de4b9fd05b1aa6 Extract to_screen() --- diff --git a/chart.c b/chart.c index 1fa76c5..cdd7477 100644 --- a/chart.c +++ b/chart.c @@ -21,11 +21,28 @@ struct BVChartPoint { float x, y; }; +struct ScreenPoint { + float x, y; +}; + G_DEFINE_TYPE_WITH_CODE(BVChart, bv_chart, GTK_TYPE_DRAWING_AREA, G_ADD_PRIVATE(BVChart)) typedef void (*cairo_draw_func)(cairo_t *cr, double x, double y); +static struct ScreenPoint to_screen(BVChartPrivate *priv, + GtkAllocation *allocation, + struct BVChartPoint *p) { + int margin = 3; + float xscale = (allocation->width - 2 * margin) / (priv->maxx - priv->minx); + float yscale = (allocation->height - 2 * margin) / (priv->miny - priv->maxy); + struct ScreenPoint screen_p = { + .x = xscale * (p->x - priv->minx) + margin, + .y = yscale * (p->y - priv->maxy) + margin, + }; + return screen_p; +} + static gboolean bv_chart_draw(GtkWidget *widget, cairo_t *cr) { BVChart *chart = BV_CHART(widget); BVChartPrivate *priv = bv_chart_get_instance_private(chart); @@ -39,9 +56,6 @@ static gboolean bv_chart_draw(GtkWidget *widget, cairo_t *cr) { GtkAllocation allocation; gtk_widget_get_allocation(widget, &allocation); - int margin = 3; - float xscale = (allocation.width - 2 * margin) / (priv->maxx - priv->minx); - float yscale = (allocation.height - 2 * margin) / (priv->miny - priv->maxy); cairo_set_source_rgb(cr, 0.0, 0.0, 1.0); float gap_threshold = 3.0; float prevx = 0.0; @@ -50,9 +64,8 @@ static gboolean bv_chart_draw(GtkWidget *widget, cairo_t *cr) { &g_array_index(priv->points, struct BVChartPoint, i); gboolean is_gap = p->x - prevx > gap_threshold; cairo_draw_func f = is_gap ? cairo_move_to : cairo_line_to; - float screen_x = xscale * (p->x - priv->minx) + margin; - float screen_y = yscale * (p->y - priv->maxy) + margin; - f(cr, screen_x, screen_y); + struct ScreenPoint screen_p = to_screen(priv, &allocation, p); + f(cr, screen_p.x, screen_p.y); prevx = p->x; } cairo_stroke(cr);