ASPPainter Documentation

Quick start instruction
   Introduction
   Methods
   Error handling

Quick start instruction

1. Quick start instruction to use ASPPainter component

• Register ASPPainter component on your computer (it's not necessary to have a web server). OpenStart->Run dialog and type "path_to_regsvr\regsvr32.exe path_to_ASPPainter\ASPPainter.dll". Make sure you specify correct paths. For example, "C:\windows\regsvr32.exe C:\ASPPainter\ASPPainter.dll". You should see "ASPPainter DLL registered successfully" message.
• Place GDI+ library (gdiplus.dll file) to the directory where ASPPainter component is located. You don't need to register gdiplus.dll
• Run block.vbs smaple located in samples folder. You can verify that newly created image has appeared (the file with the image named chart.png will be created in the root of drive C).
• Sample "Writing image to database". Create DSN "asppainter" that will point to MS Access "asppainter.mdb". Create a web-site or virtual directory

2. Quick start instruction for ASP developers

• Register ASPPainter component on your computer (it's necessary to have a Web server like IIS or PWS). Go to menu "Start", choose "Command Prompt" and change the directory to where ASPPainter component is located. Run from command line "regsvr32 ASPPainter.dll". You should see "ASPPainter DLL registered successfully" message.
• If you have problem with registration, try to specify path before regsvr32.exe and ASPPainter component. For example, "C:\windows\regsvr32.exe C:\ASPPainter\ASPPainter.dll"
• Place GDI+ library (gdiplus.dll file) to the directory where ASPPainter component is located. You don't need to register gdiplus.dll
• Place "chart.asp" from distribution package to your virtual directory.
• Open corresponding url from your browser.
  

Introduction

General information

Component is distributed with complete source code that can be easily extended with your own functionality (See purchase page). Another advantage is that you can host the component on servers where system security policy allows running only open source components.

Working with the component

Let us take a close look at the component internals on a simple sample.

Image Creation.

Used method: Create (width, height)

Create method allocates memory and creates image with specified image dimensions (width and height) in a special internal format. You should use SetBKColor to set a background color. By default the background is set to transparent black color. You need to select image type every time you need to import/export image to/from the component e.g. saving image to file, database or data stream.

Image format.

Used method: SetFormat (type)

Image format can be set with Format method. Type 0 sets PNG format (default), type 1- Jpeg, type 3 - GIF, type 4 -TIFF, type 5 - BMP.

Draw

1.Text Output.

Used method: TextOut

							
	' Define object variable
	Dim pic 
	' Create object
	Set pic = CreateObject("ASPPainter.Pictures.1")
	
	' Set background color in RGB format 	
	pic.SetBKColor 191,255,255,255
	' Create image with specified width and height 	
	pic.Create 150,75	
	
	pic.SetColor	0,0,0,255
	' Set foreground color in RGB format (black)

	'TrueType font
	pic.SetFontName "Verdana"
	pic.SetFontSize 14
	pic.SetFontBold 1	
	pic.SetFontAntialias 1
	pic.TextOut 10,40, "TrueType"
	' Save Image to file.
	pic.SaveToFile 	"C:\font.png" 	
	' Delete image and free memory
	pic.DestroyALL	
	Set pic = Nothing 
	' Clear the variable
			
	

 

2. Line.

Used method: SetLineWidth (num). Line thickness (in number of pixels) is applied for DrawLine, DrawArc and DrawPolygon methods. Default value is 1

3. Polygon.

Used method: DrawPolygon (array a, integer point_num) DrawUnclosedPolygon (array a, integer point_num),

This sample draws polygons. You need to define coordinates array and consequently fill it with x,y pairs. For example coord(0) = x1, coord(1) = y1, etc. In a call to DrawPolygon you have to specify the array and the number of points (or x, y pairs) to draw.

Save Image

Used method: SaveToFile, SaveToDatabase, SaveToStream

Image can be saved to file, database or directly to a data stream.

Destroy image

Used method: Destroy , DestroyALL

Deletes current image and frees memory. It's necessary to call this method after using every image.

 Implemented Methods:

Method	Description
ClearBrush	Clear brush data. Cancel the brush set with SetBrush
ClearFontRectangle	Clear font rectangledata. Cancel the rectangle set with SetFontRectangle
ClearFontStyle	Clear font style. Cancel the font style set with SetFontBold, SetFontItalic and etc
ClearGradient	Clear brush data. Cancel the brush set with SetGradient
ClearRegion	Cancel the region set with SetRegion.
Copy	Copy image part
Create	Create image
Destroy	Destroy image and free allocated memory
DestroyALL	Destroy images, objects and free allocated memory
DrawArc	Draw Arc
DrawBezier	Draw Bezier lines
DrawCircle	Draw circle
DrawLine	Draw line
DrawEllipse	Draw Ellipse
DrawFilledCircle	Draw filled circle
DrawFilledEllipse	Draw filled ellipse
DrawFilledPie	Draw filled pie
DrawFilledPolygon	Draw filled polygon
DrawFilledRectangle	Draw filled rectangle
DrawPie	Draw filled arc (can be used to create pie charts)
DrawPolygon	Draw polygon
DrawRectangle	Draw rectangle
ExistFont	Check if the font exists
Fill	Color fill (changing color for another color)
GetColor	Get current color in ARGB format (FFFFFFFF - white)
GetColorAlpha	Gets the alpha channel value of active foreground color
GetColorBlue	Get blue value of current color
GetColorGreen	Get green value of current color
GetColorIndex	Get color handle
GetColorRed	Get red value of current color
GetFontHeight	Get the height of a text string
GetImageIndex	Get image handle
GetPixelAlpha	Get the value of alpha channel color component
GetPixelBlue	Get blue value for a pixel
GetPixelGreen	Get green value for a pixel
GetPixelRed	Get red value for a pixel
Height	Get image height
HorizontalFlip	Flip image horizontal
LoadDatabse	Read image from database
LoadFile	Read image from file
LoadStream	Read image from variable
MakeThumbnail	Make a thumbnail from current image
Merge	Merge image parts
Mirror	Make a mirror image
ResizeCopy	Copy image part with resize
Rotate	Rotate image on an arbitrary angle
SaveToDatabase	Write image to database
SaveToFile	Write image to file
SaveToStream	Write image to variable (can be also used to write image directly to browser data stream)
SaveToVariant	Write image to variable (can be also used to write image to OleLoadPicture in VC++)
SetAlignText	Set text align data
SetBKColor	Set background color. New images will be filled with current background color. The method can be used to create transparent images
SetBlendingMode	Enables/Disables alpha blending
SetBrush	Select current image as a brush
SetColor	Set foreground color
SetColorAsTransparent	Set current color as transparent. (set alpha channel value to 0)
SetColorIndex	Select color
SetFontAntialias	Set antialias font
SetFontBold	Set bold font style
SetFontGradient	Draw text using gradient fill
SetFontItalic	Set italic font style
SetFontName	Set font name. For example to "Times New Roman"
SetFontOrientation	Set angle to draw text
SetFontRectangle	Set rectangle to draw text
SetFontRegular	Set regular font style
SetFontSize	Set the size of True Type Font
SetFontStrikeout	Set strikeout font style
SetFontUnderline	Set underline font style
SetFormat	Set image format (PNG, Jpeg, BMP, GIF, TIFF)
SetGradient	Select gradient
SetImageIndex	Select image
SetJpegQuality	Set Jpeg quality value
SetLineWidth	Set line thickness for simple drawing operations
SetPixel	Set pixel
SetRegion	Set region for painting
SetSaveAsPalette	Save current image in Palette format (PNG,TIFF, BMP). GIF image is a palette one by default
SetTransparentPixel	Set transparent pixel
TextOut	Draws text with selected TrueType font
Grayscale	Convert image to Grayscale
Monochrome	Convert image to black and white
DrawUnclosedPolygon	Draw unclosed polygon (first point is not connected to the last one)
VerticalFlip	Flip image vertical
Width	Get image width
SetBlendingQuality	Set image and text dithering quality
BlendImage	Blend two images with alpha channel
ChangeColor	Change a transparent color on another not transparent one
ChangeTransparentColor	Change a transparent color on image
SetTiffColorDepth	Set color depth for TIFF images (8,24,32)
SetTiffCompression	Reserved for future use
SetTextLineAlign	Align text vertically in a rectangle.
SetColorMatrix	Set color transformation matrix
DrawColorMatrix	Change all colors using color transformation matrix.
SetHTMLColor	Set a color from a text variable #RRGGBB
SetPalette	Set quality, desired dithering levels, and quantity of colors.

Error handling

If you want to catch errors returned from the component, you have to enable it in ASP/VBScript code, adding “On Error Resume Next”. The component throws the following exceptions:

1. Empty Image. It may happen when (a) you draw on NULL image object. Check if you called Create before calling drawing methods (b) When you save empty image to file/database/variable (c) You deleted image with Destroy or tried to call SetImageNumber with wrong image number (d) You tried to load the image of wrong format or set incorrect format in a call to SetFormat.
2. Invalid parameter. The passed parameters may have wrong type, incorrect value (blue color component is greater than 255 or negative color for example) Also this error may be thrown when you try specify more than 4998 polygon vertexes.
3. Font not found. This error may appear while drawing a text when you specified an invalid font name or when you specified a font file name that doesn't exist.
4. GDIPlus initialization error . It may happen when you didn't place gdiplus.dll to the directory of the component.
5. General error . It may appear in some unforeseen conditions (low memory, etc.).
6. Read/Write error. It may be caused by an invalid filename or file path, or when you don't have file read or file write permissions.
7. Memory initialization error. The possible cause is an attempt to create a very large file.