SDL Wrappers for Euphoria version 1

Sego SDL is a simple GUI library written for Euphoria. You can use Sego to draw and receive input from various elements including buttons, text boxes, sliders (horizontal and vertical), check boxes and menus. Sego arose from my frustration over finding that almost all of the other GUI libraries available for SDL were written for C++ and not easily transportable to Euphoria.

SDL was written by Sam Lantinga and is distributed under the GNU Lesser Public License.

SDL_TTF and SDL_GFX are distributed under the GNU Lesser Public License.

The official SDL website http://www.libsdl.org contains more information both general and specific.

2. Programs and Files

The following files are included with this SDL wrapper package:

README.RTF - this file in rich text form

README.HTML - this file in HTML form

SDL_TTF.DLL – the SDL True Type font library

SDL_GFX.DLL – the SDL Graphics library

SDL_WRAP.EW - The SDL Euphoria include file

SDL_TTF.EW - The SDL_TTF include file

SDL_GFX.EW - The SDL_GFX include file

BITMAPS - a folder containing the images used by the demo programs

FONTS - a folder containing the images used by the demo programs

Test_Sego01 – a test program, showing how to use all the Sego objects

3. The Sego Library

The Sego library is comprised of objects (the widgets such as buttons and text boxes) and routines. This section describes each the Sego object types and routines.

3.1. Objects

The attributes (location, color, size, etc.) of Sego objects are Euphoria sequences. The sequence that defines an object is specified when you create the object using the Sego_Create function.

3.1.1. Type: Button

Description: A rectangular push button.

Attribute Sequence: {x position, y position, width, height, color, highlight color, shadow color, itmap number, font number, label, text color, text x offset, text y offset, text horizontal alignment, text vertical alignment, border type}

Definitions:

x position Integer

y position Integer The x and y positions of the upper left corner of the button

width Integer

height Integer The width and height of the button in pixels

color Sequence The button face color, in RBGA format.

Where R=Red, B=Blue, G=Green, and A=Alpha

R, G, B and A range from 0-255

highlight color Sequence The color of top and left edges of the button in RGBA format

Used for a 3D effect, it’s switched with the shadow color

when the button is pressed.

shadow color Sequence The color of the bottom and right edges of the button in RGBA

format.

bitmap number Integer A bitmap number to be used as the button face instead of a solid color.

font number Integer The font number used for the label lettering

label Sequence A text label that will appear on the button

text color Sequence The text label color in RGBA format

text x offset Integer The number of pixels to shift the text label left or right

text y offset Integer The number of pixels to shift the text label up or down

Offsets are useful for changing the appearance of a button label

text horizontal alignment Left, Right, or Center

text vertical alignment Up, Down, or Center

The text alignment value determines where the button text will be
displayed on the button face.

border type Squared, Round, or None.

The border type determines whether the button will have square

square corners, round corners, or no border.

3.1.2. Type: Text Box

Description: A rectangular text box, which can be edited.

Attribute Sequence: {x position, y position, width, height, color, border color, editable, bitmap number, font number, label, text color, text x offset, text y offset, text horizontal alignment, text vertical alignment, border type, maximum text length}

Definitions:

x position Integer

y position Integer The x and y positions of the upper left corner of the text box

width Integer

height Integer The width and height of the text box in pixels

color Sequence The text box face color, in RBGA format.

border color Sequence The text box border color, in RBGA format.

editable Yes or No

If a text box is editable, you can key in changes to the text inside

bitmap number Integer A bitmap number to be used as the text box face instead of a solid color.

font number Integer The font number used for the label lettering

label Sequence A text label that will appear on the text box

text color Sequence The text label color in RGBA format

text x offset Integer The number of pixels to shift the text label left or right

text y offset Integer The number of pixels to shift the text label up or down

Offsets are useful for changing the appearance of a text box label

text horizontal alignment Left, Right, or Center

text vertical alignment Up, Down, or Center

The text alignment value determines where the text box text will be
displayed on the text box face.

border type Squared, Round, or None.

The border type determines whether the text box will have square

square corners, round corners, or no border

max text length Integer The maximum length of the label text in characters

3.1.3. Type: RButton

Description: A small round button.

Attribute Sequence: {x position, y position, outer radius, inner radius, outer color, inner color, font number, label, text color, text x offset, text y offset, text horizontal alignment, text alignment}

Definitions:

x position Integer

y position Integer The x and y positions of the center of the button

outer radius Integer The radius in pixels of the button

inner radius Integer The radius of the smaller circle in the button

outer color Integer The outer button color in RGBA format

inner color Integer The inner button color in RGBA format

font number Integer The font number used for the button

label Sequence A text label that will appear on either side of the button

text color Sequence The text label color in RGBA format

text x offset Integer The number of pixels to shift the text label left or right

text y offset Integer The number of pixels to shift the text label up or down

Offsets are useful for changing the appearance of a button label

text alignment Left or Right

The text alignment value determines whether the text label will appear to the left or right of the button

3.1.4. Type: CheckBox

Description: A small check box.

Attribute Sequence: {x position, y position, size, color, font number, label, text color, text x offset, text y offset, text horizontal alignment, text alignment}

Definitions:

x position Integer

y position Integer The x and y positions of the upper left corner of the box

size Integer The size of the check box in pixels. A check box is always square

color Integer The box color in RGBA format

font number Integer The font number used for the box

label Sequence A text label that will appear on either side of the box

text color Sequence The text label color in RGBA format

text x offset Integer The number of pixels to shift the text label left or right

text y offset Integer The number of pixels to shift the text label up or down

Offsets are useful for changing the appearance of a box label

text alignment Left or Right

The text alignment value determines whether the text label will appear to the left or right of the box

3.1.5. Type: Progress Bar

Description: A progress bar

Attribute Sequence: {x position, y position, width, height, color, border color, bitmap number}

Definitions:

x position Integer

y position Integer The x and y positions of the upper left corner of the bar

width Integer

height Integer the width and height of the bar in pixels

color Integer The bar color in RGBA format

border color Integer The bar border color in RGBA format

bitmap number Integer A bitmap number to be used for the bar instead of a solid color.

3.1.6. Type: Slider

Description: A horizontal or vertical slider control

Attribute Sequence: {x position, y position, width, height, slide size, color, highlight color, shadow color, back color, arrow color, alignment, arrow increment, slide increment}

Definitions:

x position Integer

y position Integer The x and y positions of the upper left corner of the slider

width Integer

height Integer the width and height of the slider in pixels

slider size Integer The size of the slider center (height or length) in pixels

color Integer The slider color in RGBA format

highlight color Sequence The color of top and left edges of the slider in RGBA format

shadow color Sequence The color of the bottom and right edges of the slider in RGBA

format.

back color Integer The slider back color in RGBA format

arrow color Integer The color of the scroll button arrows in RGBA format

alignment Horizontal or Vertical

arrow increment How much to increase or decrease the slider when an arrow button is pressed

slide increment How much to increase or decrease the slider when the blank area on either side of the slider center button is pressed

3.1.7. Type: Menu

Description: A menu control

Attribute Sequence: {x position, y position, width, height, entry height, color, highlight color, shadow color, select color, font number, label sequence, text color, text x offset, text y offset, text horizontal alignment, text vertical alignment}

Definitions:

x position Integer

y position Integer The x and y positions of the upper left corner of the menu

width Integer

height Integer the width and height of the menu in pixels

entry height Integer the height of each menu line in pixels

color Integer The menu color in RGBA format

highlight color Sequence The color of top and left edges of the menu in RGBA format

shadow color Sequence The color of the bottom and right edges of the menu in RGBA

format.

select color Integer The selected menu item color in RGBA format

font number Integer The font number used for the menu

label sequence Sequence Sequence containing all of the menu entries as strings.

text color Sequence The menu text color in RGBA

text select color Integer The selected menu item text color in RGBA format

text x offset Integer The number of pixels to shift the text label left or right

text y offset Integer The number of pixels to shift the text label up or down

text horizontal alignment Left, Right, or Center

text vertical alignment Up, Down, or Center

3.2. Routines

The Sego routines perform specified operations on objects.

3.2.1. Sego_Init

Syntax: Sego_Init()

Description: Initialize the Sego Library. Call this procedure once near the start of your program.

3.2.2. Sego_SetSelColor

Syntax: Sego_SetSelColor(s)

Description: Set the selected object color (the color that appears around an object when it’s been clicked). The color sequence is in RGBA format.

3.2.3. Sego_GetSelColor

Syntax: s=Sego_GetSelColor()

Description: Returns the selected object color. The color sequence is in RGBA format.

3.2.4. Sego_SetCurColor

Syntax: Sego_SetCurColor(s)

Description: Set the cursor color for editable text boxes. The color sequence is in RGBA format.

3.2.5. Sego_GetCurColor

Syntax: s=Sego_GetcurColor()

Description: Returns the cursor color for text boxes. The color sequence is in RGBA format.

3.2.6. Sego_SetLastObj

Syntax: Sego_SetLastOb(i)

Description: Set the last object number that was clicked. This value is used to determine which object will have the “selcted” box drawn around it

3.2.7. Sego_GetLastObj

Syntax: i=Sego_GetLastObj()

Description: Returns the object number of the last object clicked.

3.2.8. Sego_LoadFont

Syntax: Sego_LoadFont(s,i)

Description: Loads a TTF font file. The font path/name in string form and point-size is required.

3.2.9. Sego_NumberFonts

Syntax: i=Sego_NumberFonts()

Description: Returns the number of fonts that have been loaded.

3.2.10. Sego_SetFontStyle

Syntax: Sego_SetFontStyle(i,a)

Description: Set the font style. Requires the font number and style as arguments.

3.2.11. Sego_ClearFonts

Syntax: Sego_ClearFonts()

Description: Clear all the previously loaded fonts.

3.2.12. Sego_LoadBitmap

Syntax: Sego_LoadBitmap(s)

Description: Load a bitmap file in BMP format. The filename/path is a required argument.

3.2.13. Sego_SetBitMapTrans

Syntax: Sego_SetBitMapTrans(i1,a,i2,i3,i4)

Description: Set the transparency color for a bitmap. The bitmap number, format, red, green and blue color values are required.

3.2.14. Sego_NumberBitmaps

Syntax: i=Sego_NumberBitmaps()

Description: Returns the number of bitmaps that have been loaded.

3.2.15. Sego_ClearBitmaps

Syntax: Sego_ClearBitmaps()

Description: Clear all previously loaded bitmaps.

3.2.16. Sego_Create

Syntax: i=Sego_Create(i1, s, i2, i3)

Description: Create a new object of type i1, with attributes contained in sequence s, state value in i2, and draw value in i3. Returns an object number for the newly created object.

3.2.17. Sego_SetAttr

Syntax: Sego_SetAttr(i, s)

Description: Change the attributes in object i with sequence s.

3.2.18. Sego_GetAttr

Syntax: s=Sego_GetAttr(i)

Description: Returns the attributes for object i.

3.2.19. Sego_SetState

Syntax: Sego_SetState(i1, i2)

Description: Change the state of object i1.

3.2.20. Sego_GetState

Syntax: i2=Sego_GetState(i1)

Description: Returns the state of object i1.

3.2.21. Sego_SetDraw

Syntax: Sego_SetDraw(i1, i2)

Description: Change the drawing flag of object i1. If the drawing flag is set to “On” (or 1) then the object will be drawn in the Sego_Redraw procedure.

3.2.22. Sego_GetDraw

Syntax: i2=Sego_GetDraw(i1)

Description: Returns the drawing flag of object i1.

3.2.23. Sego_NumberObjects

Syntax: i=Sego_NumberObjects()

Description: Returns the number of objects that have been created.

3.2.24. Sego_ClearObjects

Syntax: Sego_ClearObjects()

Description: Clears (deletes) all of the objects that have been created.

3.2.25. Sego_Redraw

Syntax: Sego_Redraw(i)

Description: Redraws all the objects. Use the Sego_Setdraw routine to hide an object.

3.2.26. Sego_Update

Syntax: s=Sego_Update(i)

Description: Returns a sequence containing the number and state of the last object touched.

3.2.27. Sego_Quit

Syntax: s=Sego_Quit(i)

Description: Clear all objects and close SDL.

4. Epilogue and Coda

There are a few necessary omissions from this first version that I simply didn’t have the time or skills to include. First off, the code could’ve been more modular to accommodate new object types. The update/redraw loops work fairly well, but a more elegant way would’ve been to use SDL user events. I’ll try to address those issues in the next Sego version.

Send comments & feedback to mkakita@juno.com