First Commit

libui-ng/old/_wip/examples_drawtext/basic.c

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+// 17 january 2017
+#include "drawtext.h"
+
+static const char *text =
+	"It is with a kind of fear that I begin to write the history of my life. "
+	"I have, as it were, a superstitious hesitation in lifting the veil that "
+	"clings about my childhood like a golden mist. The task of writing an "
+	"autobiography is a difficult one. When I try to classify my earliest "
+	"impressions, I find that fact and fancy look alike across the years that "
+	"link the past with the present. The woman paints the child's experiences "
+	"in her own fantasy. A few impressions stand out vividly from the first "
+	"years of my life; but \"the shadows of the prison-house are on the rest.\" "
+	"Besides, many of the joys and sorrows of childhood have lost their "
+	"poignancy; and many incidents of vital importance in my early education "
+	"have been forgotten in the excitement of great discoveries. In order, "
+	"therefore, not to be tedious I shall try to present in a series of "
+	"sketches only the episodes that seem to me to be the most interesting "
+	"and important."
+	"";
+static char fontFamily[] = "Palatino";
+// TODO should be const; look at constructor function?
+static uiDrawFontDescriptor defaultFont = {
+	.Family = fontFamily,
+	.Size = 18,
+	.Weight = uiDrawTextWeightNormal,
+	.Italic = uiDrawTextItalicNormal,
+	.Stretch = uiDrawTextStretchNormal,
+};
+static uiAttributedString *attrstr;
+static uiDrawTextLayoutParams params;
+
+#define margins 10
+
+static uiBox *panel;
+static uiCheckbox *showExtents;
+static uiCheckbox *showLineBounds;
+static uiCheckbox *showLineGuides;
+
+// TODO should this be const?
+static double strokeDashes[] = { 5, 2 };
+// TODO this should be const
+static uiDrawStrokeParams strokeParams = {
+	.Cap = uiDrawLineCapFlat,
+	.Join = uiDrawLineJoinMiter,
+	.Thickness = 1,
+	.MiterLimit = uiDrawDefaultMiterLimit,
+	.Dashes = strokeDashes,
+	.NumDashes = 2,
+	.DashPhase = 0,
+};
+
+// TODO should be const?
+static uiDrawBrush fillBrushes[4] = {
+	{
+		.Type = uiDrawBrushTypeSolid,
+		.R = 1.0,
+		.G = 0.0,
+		.B = 0.0,
+		.A = 0.5,
+	},
+	{
+		.Type = uiDrawBrushTypeSolid,
+		.R = 0.0,
+		.G = 1.0,
+		.B = 0.0,
+		.A = 0.5,
+	},
+	{
+		.Type = uiDrawBrushTypeSolid,
+		.R = 0.0,
+		.G = 0.0,
+		.B = 1.0,
+		.A = 0.5,
+	},
+	{
+		.Type = uiDrawBrushTypeSolid,
+		.R = 0.0,
+		.G = 1.0,
+		.B = 1.0,
+		.A = 0.5,
+	},
+};
+// TODO come up with better colors
+static uiDrawBrush strokeBrushes[3] = {
+	// baseline
+	{
+		.Type = uiDrawBrushTypeSolid,
+		.R = 0.5,
+		.G = 0.5,
+		.B = 0.0,
+		.A = 0.75,
+	},
+	// ascent
+	{
+		.Type = uiDrawBrushTypeSolid,
+		.R = 1.0,
+		.G = 0.0,
+		.B = 1.0,
+		.A = 0.75,
+	},
+	// descent
+	{
+		.Type = uiDrawBrushTypeSolid,
+		.R = 0.5,
+		.G = 0.75,
+		.B = 1.0,
+		.A = 0.75,
+	},
+};
+
+static void draw(uiAreaDrawParams *p)
+{
+	uiDrawPath *path;
+	uiDrawTextLayout *layout;
+	uiDrawBrush b;
+
+	b.Type = uiDrawBrushTypeSolid;
+
+	// only clip the text, not the guides
+	uiDrawSave(p->Context);
+
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathAddRectangle(path, margins, margins,
+		p->AreaWidth - 2 * margins,
+		p->AreaHeight - 2 * margins);
+	uiDrawPathEnd(path);
+	uiDrawClip(p->Context, path);
+	uiDrawFreePath(path);
+
+	// TODO get rid of this later
+#if 0
+	path = uiDrawNewPath(uiDrawFillModeWinding);
+	uiDrawPathAddRectangle(path, -100, -100,
+		p->AreaWidth * 2,
+		p->AreaHeight * 2);
+	uiDrawPathEnd(path);
+	b.R = 0.0;
+	b.G = 1.0;
+	b.B = 0.0;
+	b.A = 1.0;
+	uiDrawFill(p->Context, path, &b);
+	uiDrawFreePath(path);
+#endif
+
+	params.Width = p->AreaWidth - 2 * margins;
+	layout = uiDrawNewTextLayout(&params);
+	uiDrawText(p->Context, layout, margins, margins);
+
+	uiDrawRestore(p->Context);
+
+	if (uiCheckboxChecked(showExtents)) {
+		double width, height;
+
+		uiDrawTextLayoutExtents(layout, &width, &height);
+		path = uiDrawNewPath(uiDrawFillModeWinding);
+		uiDrawPathAddRectangle(path, margins, margins,
+			width, height);
+		uiDrawPathEnd(path);
+		b.R = 1.0;
+		b.G = 0.0;
+		b.B = 1.0;
+		b.A = 0.5;
+		uiDrawStroke(p->Context, path, &b, &strokeParams);
+		uiDrawFreePath(path);
+	}
+
+	if (uiCheckboxChecked(showLineBounds) || uiCheckboxChecked(showLineGuides)) {
+		uiDrawTextLayoutLineMetrics m;
+		int i, n;
+		int fill = 0;
+
+		n = uiDrawTextLayoutNumLines(layout);
+		for (i = 0; i < n; i++) {
+			uiDrawTextLayoutLineGetMetrics(layout, i, &m);
+
+			if (uiCheckboxChecked(showLineBounds)) {
+				path = uiDrawNewPath(uiDrawFillModeWinding);
+				uiDrawPathAddRectangle(path, margins + m.X, margins + m.Y,
+					m.Width, m.Height);
+				uiDrawPathEnd(path);
+				uiDrawFill(p->Context, path, fillBrushes + fill);
+				uiDrawFreePath(path);
+				fill = (fill + 1) % 4;
+			}
+			if (uiCheckboxChecked(showLineGuides)) {
+				// baseline
+				path = uiDrawNewPath(uiDrawFillModeWinding);
+				uiDrawPathNewFigure(path,
+					margins + m.X,
+					margins + m.BaselineY);
+				uiDrawPathLineTo(path,
+					margins + m.X + m.Width,
+					margins + m.BaselineY);
+				uiDrawPathEnd(path);
+				uiDrawStroke(p->Context, path, &(strokeBrushes[0]), &strokeParams);
+				uiDrawFreePath(path);
+
+				// ascent line
+				path = uiDrawNewPath(uiDrawFillModeWinding);
+				uiDrawPathNewFigure(path,
+					margins + m.X,
+					margins + m.BaselineY - m.Ascent);
+				uiDrawPathLineTo(path,
+					margins + m.X + m.Width,
+					margins + m.BaselineY - m.Ascent);
+				uiDrawPathEnd(path);
+				uiDrawStroke(p->Context, path, &(strokeBrushes[1]), &strokeParams);
+				uiDrawFreePath(path);
+
+				// descent line
+				path = uiDrawNewPath(uiDrawFillModeWinding);
+				uiDrawPathNewFigure(path,
+					margins + m.X,
+					margins + m.BaselineY + m.Descent);
+				uiDrawPathLineTo(path,
+					margins + m.X + m.Width,
+					margins + m.BaselineY + m.Descent);
+				uiDrawPathEnd(path);
+				uiDrawStroke(p->Context, path, &(strokeBrushes[2]), &strokeParams);
+				uiDrawFreePath(path);
+			}
+		}
+	}
+
+	uiDrawFreeTextLayout(layout);
+}
+
+static struct example basicExample;
+
+// TODO share?
+static void checkboxChecked(uiCheckbox *c, void *data)
+{
+	redraw();
+}
+
+static uiCheckbox *newCheckbox(const char *text)
+{
+	uiCheckbox *c;
+
+	c = uiNewCheckbox(text);
+	uiCheckboxOnToggled(c, checkboxChecked, NULL);
+	uiBoxAppend(panel, uiControl(c), 0);
+	return c;
+}
+
+struct example *mkBasicExample(void)
+{
+	panel = uiNewVerticalBox();
+	showExtents = newCheckbox("Show Layout Extents");
+	showLineBounds = newCheckbox("Show Line Bounds");
+	showLineGuides = newCheckbox("Show Line Guides");
+
+	basicExample.name = "Basic Paragraph of Text";
+	basicExample.panel = uiControl(panel);
+	basicExample.draw = draw;
+	basicExample.mouse = NULL;
+	basicExample.key = NULL;
+
+	attrstr = uiNewAttributedString(text);
+	params.String = attrstr;
+	params.DefaultFont = &defaultFont;
+	params.Align = uiDrawTextAlignLeft;
+
+	return &basicExample;
+}
+
+// TODO on GTK+ an area by itself in a window doesn't get expand properties set properly?