refine a-eq inline display size + grid

diff --git a/libs/plugins/a-eq.lv2/a-eq.c b/libs/plugins/a-eq.lv2/a-eq.c
index 380e1ba3e59710664f81e96060289ad9b7f73167..a539c908258b7ef7c22340e6d5fe00dc8c4ebee4 100644 (file)
--- a/libs/plugins/a-eq.lv2/a-eq.c
+++ b/libs/plugins/a-eq.lv2/a-eq.c
@@ -492,7 +492,7 @@ static LV2_Inline_Display_Image_Surface *
 render_inline (LV2_Handle instance, uint32_t w, uint32_t max_h)
 {
        Aeq* self = (Aeq*)instance;
-       uint32_t h = MIN (w * 9 / 16, max_h);
+       uint32_t h = MIN (1 | (uint32_t)ceilf (w * 9.f / 16.f), max_h);
 
        if (!self->display || self->w != w || self->h != h) {
                if (self->display) cairo_surface_destroy(self->display);
@@ -510,19 +510,30 @@ render_inline (LV2_Handle instance, uint32_t w, uint32_t max_h)
 
        cairo_set_line_width(cr, 1.0);
 
-       // draw grid 5dB steps
-       const double dash2[] = {1, 3};
+       // prepare grid drawing
        cairo_save (cr);
-       cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
+       const double dash2[] = {1, 3};
+       //cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
        cairo_set_dash(cr, dash2, 2, 2);
        cairo_set_source_rgba (cr, 0.5, 0.5, 0.5, 0.5);
 
-       for (uint32_t d = 1; d < 8; ++d) {
-               const float y = -.5 + floorf (h * (d * 5.f / 40.f));
+       // draw x-grid 6dB steps
+       for (int32_t d = -18; d <= 18; d+=6) {
+               float y = (float)h * (d / 40.0 + 0.5);
+               y = rint (y) - .5;
                cairo_move_to (cr, 0, y);
                cairo_line_to (cr, w, y);
                cairo_stroke (cr);
        }
+       // draw y-axis grid 100, 1k, 10K
+       for (int32_t f = 100; f <= 10000; f *= 10) {
+               float x = w * log10 (f / 20.0) / log10 (1000.0);
+               x = rint (x) - .5;
+               cairo_move_to (cr, x, 0);
+               cairo_line_to (cr, x, h);
+               cairo_stroke (cr);
+       }
+
        cairo_restore (cr);