Started writing the vector graphics API.

gtkarea/area.c

@@ -1,10 +1,6 @@
 // 4 september 2015
 #include "area.h"
 
-struct uiDrawContext {
-	cairo_t *cr;
-};
-
 struct areaPrivate {
 	uiArea *a;
 	uiAreaHandler *ah;
@@ -125,10 +121,8 @@ static gboolean areaWidget_draw(GtkWidget *w, cairo_t *cr)
 	struct areaPrivate *ap = a->priv;
 	uiAreaDrawParams dp;
 	double clipX0, clipY0, clipX1, clipY1;
-	uiDrawContext ctxt;
 
-	ctxt.cr = cr;
-	dp.Context = &ctxt;
+	dp.Context = newContext(cr);
 
 	dp.ClientWidth = ap->clientWidth;
 	dp.ClientHeight = ap->clientHeight;
@@ -152,6 +146,7 @@ static gboolean areaWidget_draw(GtkWidget *w, cairo_t *cr)
 
 	(*(ap->ah->Draw))(ap->ah, ap->a, &dp);
 
+	g_free(dp.Context);
 	return FALSE;
 }
 

gtkarea/area.h

@@ -31,3 +31,5 @@ extern GType areaWidget_get_type(void);
 
 extern GtkWidget *newArea(uiAreaHandler *ah);
 extern void areaUpdateScroll(GtkWidget *area);
+
+extern uiDrawContext *newContext(cairo_t *);

gtkarea/draw.c

@@ -0,0 +1,75 @@
+// 6 september 2015
+#include "area.h"
+
+struct uiDrawContext {
+	cairo_t *cr;
+	gboolean hasPath;
+};
+
+uiDrawContext *newContext(cairo_t *cr)
+{
+	uiDrawContext *c;
+
+	c = (uiDrawContext *) g_malloc0(sizeof (uiDrawContext));
+	c->cr = cr;
+	c->hasPath = FALSE;
+	return c;
+}
+
+static void prepPath(uiDrawContext *c)
+{
+	if (c->hasPath)
+		return;
+	cairo_new_path(c->cr);
+	c->hasPath = TRUE;
+}
+
+void uiDrawMoveTo(uiDrawContext *c, intmax_t x, intmax_t y)
+{
+	prepPath(c);
+	cairo_move_to(c->cr, (double) x + 0.5, (double) y + 0.5);
+}
+
+void uiDrawLineTo(uiDrawContext *c, intmax_t x, intmax_t y)
+{
+	prepPath(c);
+	cairo_line_to(c->cr, (double) x + 0.5, (double) y + 0.5);
+}
+
+#define R(c) (((c) >> 16) & 0xFF)
+#define G(c) (((c) >> 8) & 0xFF)
+#define B(c) ((c) & 0xFF)
+
+void uiDrawStroke(uiDrawContext *c, uiDrawStrokeParams *p)
+{
+	cairo_set_source_rgb(c->cr,
+		((double) R(p->RGB)) / 255,
+		((double) G(p->RGB)) / 255,
+		((double) B(p->RGB)) / 255);
+	switch (p->Cap) {
+	case uiDrawLineCapFlat:
+		cairo_set_line_cap(c->cr, CAIRO_LINE_CAP_BUTT);
+		break;
+	case uiDrawLineCapRound:
+		cairo_set_line_cap(c->cr, CAIRO_LINE_CAP_ROUND);
+		break;
+	case uiDrawLineCapSquare:
+		cairo_set_line_cap(c->cr, CAIRO_LINE_CAP_SQUARE);
+		break;
+	}
+	switch (p->Join) {
+	case uiDrawLineJoinMiter:
+		cairo_set_line_join(c->cr, CAIRO_LINE_JOIN_MITER);
+		cairo_set_miter_limit(c->cr, p->MiterLimit);
+		break;
+	case uiDrawLineJoinRound:
+		cairo_set_line_join(c->cr, CAIRO_LINE_JOIN_ROUND);
+		break;
+	case uiDrawLineJoinBevel:
+		cairo_set_line_join(c->cr, CAIRO_LINE_JOIN_BEVEL);
+		break;
+	}
+	cairo_set_line_width(c->cr, p->Thickness);
+	cairo_stroke(c->cr);
+	c->hasPath = FALSE;
+}

gtkarea/main.c

@@ -12,9 +12,27 @@ static struct handler h;
 static GtkWidget *nhspinb;
 static GtkWidget *nvspinb;
 
-static void handlerDraw(uiAreaHandler *a, uiArea *area, uiAreaDrawParams *params)
+static void handlerDraw(uiAreaHandler *a, uiArea *area, uiAreaDrawParams *p)
 {
-	// TODO
+	uiDrawStrokeParams sp;
+
+	uiDrawMoveTo(p->Context, p->ClipX + 5, p->ClipY + 5);
+	uiDrawLineTo(p->Context, (p->ClipX + p->ClipWidth) - 5, (p->ClipY + p->ClipHeight) - 5);
+	sp.RGB = 0xFF0000;
+	sp.Cap = uiDrawLineCapFlat;
+	sp.Join = uiDrawLineJoinMiter;
+	sp.Thickness = 1;
+	sp.MiterLimit = 10;
+	uiDrawStroke(p->Context, &sp);
+
+	uiDrawMoveTo(p->Context, p->ClipX, p->ClipY);
+	uiDrawLineTo(p->Context, p->ClipX + p->ClipWidth, p->ClipY);
+	sp.RGB = 0x000080;
+	sp.Cap = uiDrawLineCapFlat;
+	sp.Join = uiDrawLineJoinMiter;
+	sp.Thickness = 1;
+	sp.MiterLimit = 10;
+	uiDrawStroke(p->Context, &sp);
 }
 
 static uintmax_t handlerHScrollMax(uiAreaHandler *a, uiArea *area)

gtkarea/ui.h

@@ -29,3 +29,40 @@ struct uiAreaDrawParams {
 	intmax_t HScrollPos;
 	intmax_t VScrollPos;
 };
+
+// TODO default miter limit?
+// cairo - 10.0
+// GDI - ?
+// Core Graphics - ?
+
+// TODO dotting/dashing
+
+typedef struct uiDrawStrokeParams uiDrawStrokeParams;
+typedef enum uiDrawLineCap uiDrawLineCap;
+typedef enum uiDrawLineJoin uiDrawLineJoin;
+
+typedef uint32_t uiRGB;
+
+enum uiDrawLineCap {
+	uiDrawLineCapFlat,
+	uiDrawLineCapRound,
+	uiDrawLineCapSquare,
+};
+
+enum uiDrawLineJoin {
+	uiDrawLineJoinMiter,
+	uiDrawLineJoinRound,
+	uiDrawLineJoinBevel,
+};
+
+struct uiDrawStrokeParams {
+	uiRGB RGB;
+	uiDrawLineCap Cap;
+	uiDrawLineJoin Join;
+	intmax_t Thickness;
+	intmax_t MiterLimit;
+};
+
+void uiDrawMoveTo(uiDrawContext *, intmax_t, intmax_t);
+void uiDrawLineTo(uiDrawContext *, intmax_t, intmax_t);
+void uiDrawStroke(uiDrawContext *, uiDrawStrokeParams *);