Welcome to Part 8 of the HP Prime Tutorial. Continuing in our drawing commands, we are going to feature ARC and LINE.

Syntax:

Cartesian:

ARC(x, y, r, angle 1*, angle 2*, color*).

Pixels:

ARC_P(x, y, r, angle 1*, angle 2*, color*)

x: x coordinate

y: y coordinate

r: length of the radius in pixels. This is why I prefer using pixel commands in my programming.

angle 1 and angle 2: If included, these two arguments draw an arc segment. The angle follows the conventional circle notation, starting with 0 (due east) going counter clockwise. Use the current angle mode.

color: color of the arc. To use it, angle 1 and angle 2 must be included.

Draws a line segment from (x1, y1) to (x2, y2). The color is optional.

Syntax:

Cartesian:

LINE(x1, y1, x2, y2, color*)

Pixels:

LINE_P(x1, y1, x2, y2, color*)

The next to programs CIRCLE1 and CIRCLE2 do the same thing: draw a circle, label quadrants and angels. The reason why I am posting these two is that when you are programming graphics, care must be given. Adjustments to where graphics are placed can be necessary and I hope CIRCLE1 and CIRCLE2 illustrates this.

Medium font is assumed (set in Home Settings).

The angle symbol (°) get be retrieved by pressing Shift + 9 and selecting ° from the grid.

CIRCLE1 (the "rough draft", if you will):

EXPORT CIRCLE1()

BEGIN

RECT();

TEXTOUT_P("Circle", 0, 0);

TEXTOUT_P("II",109,59);

TEXTOUT_P("90°",159,59);

TEXTOUT_P("I",209,59);

TEXTOUT_P("180°",109,109);

TEXTOUT_P("0°",209,109);

TEXTOUT_P("III",109,159);

TEXTOUT_P("270°",159,159);

TEXTOUT_P("IV",209,159);

LINE_P(0,109,318,109,RGB(16,16,16));

LINE_P(159,0,159,239,RGB(16,16,16));

ARC_P(159,109,30);

FREEZE;

END;

The results:

**ARC and ARC_P**: Draws a Circle or a Circular ArcSyntax:

Cartesian:

ARC(x, y, r, angle 1*, angle 2*, color*).

Pixels:

ARC_P(x, y, r, angle 1*, angle 2*, color*)

x: x coordinate

y: y coordinate

r: length of the radius in pixels. This is why I prefer using pixel commands in my programming.

angle 1 and angle 2: If included, these two arguments draw an arc segment. The angle follows the conventional circle notation, starting with 0 (due east) going counter clockwise. Use the current angle mode.

color: color of the arc. To use it, angle 1 and angle 2 must be included.

**LINE and LINE_P**Draws a line segment from (x1, y1) to (x2, y2). The color is optional.

Syntax:

Cartesian:

LINE(x1, y1, x2, y2, color*)

Pixels:

LINE_P(x1, y1, x2, y2, color*)

The next to programs CIRCLE1 and CIRCLE2 do the same thing: draw a circle, label quadrants and angels. The reason why I am posting these two is that when you are programming graphics, care must be given. Adjustments to where graphics are placed can be necessary and I hope CIRCLE1 and CIRCLE2 illustrates this.

Medium font is assumed (set in Home Settings).

The angle symbol (°) get be retrieved by pressing Shift + 9 and selecting ° from the grid.

CIRCLE1 (the "rough draft", if you will):

EXPORT CIRCLE1()

BEGIN

RECT();

TEXTOUT_P("Circle", 0, 0);

TEXTOUT_P("II",109,59);

TEXTOUT_P("90°",159,59);

TEXTOUT_P("I",209,59);

TEXTOUT_P("180°",109,109);

TEXTOUT_P("0°",209,109);

TEXTOUT_P("III",109,159);

TEXTOUT_P("270°",159,159);

TEXTOUT_P("IV",209,159);

LINE_P(0,109,318,109,RGB(16,16,16));

LINE_P(159,0,159,239,RGB(16,16,16));

ARC_P(159,109,30);

FREEZE;

END;

The results:

This is good, but we can do better. First I am going to move the labels II, 180°, and III 10 pixels to the left, primarily so the 180° label does not touch the circle.

Second I am going to move the labels III, 270°, and IV up 10 pixels to make the bottom line look better and not "so far away" from the circle.

Although it is not necessarily, I am going to make the angle labels blue. I will need to specify the font size code at 0.

Finally, I find that the lines are too dark. I am going to make them a bit more gray.

Here is the second revision. For the purposes of this tutorial, I call this program CIRCLE2. All changes are in bold.

EXPORT CIRCLE1()

BEGIN

RECT();

TEXTOUT_P("Circle", 0, 0);

TEXTOUT_P("II",

TEXTOUT_P("90°",159,59,

TEXTOUT_P("I",209,59);

TEXTOUT_P("180°",

TEXTOUT_P("0°",209,109,

TEXTOUT_P("III",

TEXTOUT_P("270°",159,

TEXTOUT_P("IV",209,

LINE_P(0,109,318,109,

LINE_P(159,0,159,239,

ARC_P(159,109,30);

FREEZE;

END;

Second I am going to move the labels III, 270°, and IV up 10 pixels to make the bottom line look better and not "so far away" from the circle.

Although it is not necessarily, I am going to make the angle labels blue. I will need to specify the font size code at 0.

Finally, I find that the lines are too dark. I am going to make them a bit more gray.

Here is the second revision. For the purposes of this tutorial, I call this program CIRCLE2. All changes are in bold.

EXPORT CIRCLE1()

BEGIN

RECT();

TEXTOUT_P("Circle", 0, 0);

TEXTOUT_P("II",

**99**,59);TEXTOUT_P("90°",159,59,

**0,RGB(0,0,255)**);TEXTOUT_P("I",209,59);

TEXTOUT_P("180°",

**99**,109,**0,RGB(0,0,255)**);TEXTOUT_P("0°",209,109,

**0,RGB(0,0,255)**);TEXTOUT_P("III",

**99**,**149**);TEXTOUT_P("270°",159,

**149,0,RGB(0,0,255)**);TEXTOUT_P("IV",209,

**149**);LINE_P(0,109,318,109,

**RGB(128,128,128)**);LINE_P(159,0,159,239,

**RGB(128,128,128)**);ARC_P(159,109,30);

FREEZE;

END;

A better looking picture.

As always, thanks for your time, comments, and questions. Hopefully this session is helpful.

This blog is property of Edward Shore. 2013

Eddie

As always, thanks for your time, comments, and questions. Hopefully this session is helpful.

This blog is property of Edward Shore. 2013

Eddie

** Note: Thanks to Dennis for pointing out my typo. It is corrected now. 3/5/2014