Learn more about GDI + [93]: tgpimage (13)-adjust the three primary colors of red, green, and blue and the transparency of the image

In this example:

Code file:

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls, comctrls; Type tform1 = Class (tform) trackbar1: ttrackbar; trackbar2: ttrackbar; trackbar3: ttrackbar; trackbar4: ttrackbar; label1: tlabel; label2: tlabel; label3: tlabel; label4: tlabel; Procedure alert (Sender: tobject); Procedure alert (Sender: tobject); Procedure future (Sender: tobject); Procedure trackbar1change (Sender: tobject); Procedure future (Sender: tobject); end; var form1: tform1; implementation {$ R *. DFM} uses gdipobj, gdipapi; var IMG: tgpimage; var colormatrix: tcolormatrix = (1.0, 0.0, 0.0, 0.0, 0.0), (0.0, 1.0, 0.0, 0.0, 0.0), (0.0, 0.0, 1.0, 0.0, 0.0), (0.0, 0.0, 0.0, 1.0, 0.0, 0.0), (0.0, 0.0, 0.0, 1.0 )); procedure tform1.formcreate (Sender: tobject); begin IMG: = tgpimage. create ('C: \ temp \ test.png '); {This is a specially crafted color test image} trackbar1.height: = 23; trackbar1.showselrange: = false; trackbar1.max: = 100; trackbar1.position: = trackbar1.max; trackbar2.height: = 23; trackbar2.showselrange: = false; trackbar2.max: = 100; trackbar2.position: = trackbar2.max; trackbar3.height: = 23; Category: = false; trackbar3.max: = 100; trackbar3.position: = trackbar3.max; trackbar4.height: = 23; trackbar4.showselrange: = false; trackbar4.max: = 100; trackbar4.position: = trackbar4.max; doublebuffered: = true; end; procedure invoke (Sender: tobject ); begin IMG. free; end; Procedure tform1.formpaint (Sender: tobject); var G: tgpgraphics; imageattributes: tgpimageattributes; begin G: = tgpgraphics. create (canvas. handle); imageattributes: = tgpimageattributes. create; colormatrix [100]: = trackbar1.position/100; {adjusted red} colormatrix [100]: = trackbar2.position/; {adjusted green} colormatrix []: = trackbar3.position; {adjust blue} colormatrix [3, 3]: = trackbar4.position/100; {adjust transparency} imageattributes. setcolormatrix (colormatrix); G. drawimage (IMG, {image to be drawn} makerect (10, 10, IMG. getwidth, IMG. getheight), {the image will be scaled down to fit this rectangle} 0, 0, {drawing position} IMG. getwidth, IMG. getheight, {size} unitpixel, {unit} imageattributes {image attribute}); imageattributes. free; G. free; end; Procedure tform1.trackbar1change (Sender: tobject); begin repaint; end; Procedure prepare (Sender: tobject); begin repaint; end; Procedure tform1.trackbar3change (Sender: tobject ); begin repaint; end; Procedure tform1.trackbar4change (Sender: tobject); begin repaint; end.
 

Form file:

object Form1: TForm1  Left = 0  Top = 0  Caption = 'Form1'  ClientHeight = 259  ClientWidth = 219  Color = clBtnFace  Font.Charset = DEFAULT_CHARSET  Font.Color = clWindowText  Font.Height = -11  Font.Name = 'Tahoma'  Font.Style = []  OldCreateOrder = False  Position = poDesktopCenter  OnCreate = FormCreate  OnDestroy = FormDestroy  OnPaint = FormPaint  PixelsPerInch = 96  TextHeight = 13  object Label1: TLabel    Left = 23    Top = 160    Width = 24    Height = 13    Caption = #32418#33394  end  object Label2: TLabel    Left = 23    Top = 184    Width = 24    Height = 13    Caption = #32511#33394  end  object Label3: TLabel    Left = 23    Top = 206    Width = 24    Height = 13    Caption = #34013#33394  end  object Label4: TLabel    Left = 11    Top = 230    Width = 36    Height = 13    Caption = #36879#26126#24230  end  object TrackBar1: TTrackBar    Left = 48    Top = 157    Width = 164    Height = 45    TabOrder = 0    OnChange = TrackBar1Change  end  object TrackBar2: TTrackBar    Left = 48    Top = 179    Width = 164    Height = 45    TabOrder = 1    OnChange = TrackBar2Change  end  object TrackBar3: TTrackBar    Left = 48    Top = 201    Width = 163    Height = 45    TabOrder = 2    OnChange = TrackBar3Change  end  object TrackBar4: TTrackBar    Left = 48    Top = 224    Width = 163    Height = 45    TabOrder = 3    OnChange = TrackBar4Change  endend